IC-NRLF 


B    M    IDb 


UNIVERSITY   OF   CALIFORNIA 


DEPARTMENT  OF  EDUCATION 


GIFT  OF  THE   PUBLISHER 


No. 


Received 


A   STUDY    IN    THE   ANATOMY   OF  THE    HUMAN    BODY 
(For  explanation  of  this  Frontispiece  see  page  vii) 


OUR  BODIES  AND  HOW 
WE  LIVE 


AN  ELEMENTARY  TEXT-BOOK   OF 

PHYSIOLOGY  AND   HYGIENE 

FOR   USE  IN  SCHOOLS 


BY 


ALBERT  F.  BLAISDELL,  M.D. 
•^ 

AUTHOR  OF  "  CHILD'S  BOOK  OF  HEALTH,"  "  How  TO  KEEP  WELL, 
"LIFE  AND  HEALTH,"  "PRACTICAL  PHYSIOLOGY,"  ETC.,  ETC. 


REVISED   EDITION 


BOSTON,  U.S.A.,  AND  LONDON 
GINN  &  COMPANY,   PUBLISHERS 


1904 


BLAISDELL'S 
SERIES  OF  PHYSIOLOGIES 

By  ALBERT  F.  BLAISDELL,  M.D. 
CHILD'S  BOOK  OF  HEALTH 

In  easy  lessons  for  primary  grades.  List  price, 
30  cents. 

HOW  TO  KEEP  WELL 

A  text-book  on  health  for  the  lower  grades.  List 
price,  45  cents. 

OUR  BODIES  AND  HOW  WE  LIVE 

REVISED  EDITION.  An  elementary  text-book 
of  physiology  and  hygiene  for  use  in  schools.  List 
price,  65  cents. 

LIFE  AND  HEALTH 

A  text-book  on  physiology  and  hygiene  for  high 
schools,  academies,  and  normal  schools.  List  price, 
90  cents. 

PRACTICAL  PHYSIOLOGY 

A  text-book  for  higher  schools.    List  price,  $1.10. 

How  TO  TEACH  PHYSIOLOGY 

A  handbook  for  teachers.    List  price,  10  cents. 

GINN   &  COMPANY   Publishers 


ENTERED  AT  STATIONERS'  HALL 


COPYRIGHT,  1884,  1892 
BY  LEE  AND  SHEPARD 


COPYRIGHT,  1893,  1904 
BY   ALBERT   F.   BLAISDELL 

ALL   RIGHTS   RESERVED 


PREFACE   TO   REVISED   EDITION 


It  is  now  twenty  years  since  this  book  was  first  pub- 
lished and  ten  years  since  it  was  revised  and  reprinted. 
Meanwhile  many  important  discoveries  have  been  made 
concerning  the  nature  and  propagation  of  bacteria,  and 
many  changes  have  taken  place  in  the  attitude  of  scien- 
tific men  towards  the  causes  and  restrictions  of  contagious 
diseases  and  the  promotion  of  personal  and  public  health. 

The  author  has  taken  advantage  of  the  demand  for 
another  revision  to  rewrite,  rearrange,  and  illustrate  this 
book  in  accord  with  the  latest  teachings  in  this  branch 
of  science. 

In  this  edition,  as  in  previous  editions,  it  has  been  the 
aim  of  the  author  to  prepare  a  text-book  for  elementary 
schools  which  should  set  forth  clearly  and  tersely  the  more 
important  and  interesting  facts  about  our  bodily  life. 

It  is  believed  that  boys  and  girls  in  elementary  schools 
should  have  an  opportunity  to  learn  a  few  essential  things 
about  the  anatomy  and  physiology  of  their  own  bodies. 
These  facts  in  themselves  are  of  comparatively  little  worth 
unless  they  become  the  means  of  enabling  our  young  folks 
to  understand  thoroughly  the  simple  laws  of  health  and  to 
apply  them  intelligently  to  their  daily  living.  With  this 
in  mind,  the  author  has  aimed  to  lay  marked  emphasis 

Hi 


iv  PREFACE   TO   REVISED   EDITION 

in  each  chapter  on  such  points  as  bear  directly  upon 
personal  health. 

In  this  book,  as  in  the  other  books  of  this  series  of 
school  physiologies,  there  has  been  added  to  the  text  a 
number  of  carefully  graded  and  practical  experiments  suffi- 
ciently varied  to  allow  a  wide  range  of  choice.  For  the  most 
part  they  are  simple  and  can  be  performed  with  apparatus 
that  is  inexpensive  and  easily  obtained. 

This  book  complies  fully  with  the  laws  of  those  states 
which  require  in  their  public  schools  the  study  of  the 
nature  and  effect  of  alcohol,  tobacco,  and  other  narcotics 
upon  the  human  system. 

The  author  would  acknowledge  his  indebtedness  to  Dr. 
Margaret  B.  Wilson  of  the  New  York  Normal  College  for 
careful  criticism  of  his  manuscript  and  for  valuable  assist- 
ance and  suggestions  in  reading  the  proofs,  and  also  to 
Professor  H.  W.  Conn  of  Wesleyan  University  for  the  use 
of  a  number  of  illustrations  from  his  work  on  bacteria, 
recently  issued  by  the  publishers  of  this  book. 

A.  F.  BLAISDELL 

WINCHESTER,  MASS. 
March,  1904 


CONTENTS 


CHAPTER    I 
INTRODUCTION  


CHAPTER   II 
THE  BONY  FRAMEWORK 16 

CHAPTER   III 
THE  MUSCLES  AND  HOW  TO  USE  THEM 44 

CHAPTER  IV 
FOOD  AND  DRINK 69 

CHAPTER   V 
ORIGIN  AND  NATURE  OF  FERMENTED  DRINKS 80 

CHAPTER   VI 
THE  DIGESTION  OF  FOOD 100 

CHAPTER  VII 
THE  CIRCULATION  OF  THE  BLOOD 133 

CHAPTER  VIII 
BREATHING .  161 


VI  CONTENTS 

CHAPTER  IX 

PAGE 

THE  SKIN  AND  THE  KIDNEYS 185 

CHAPTER   X 
THE  NERVOUS  SYSTEM 211 

CHAPTER   XI 
THE  SPECIAL  SENSES 246 

CHAPTER   XII 
THE  THROAT  AND  THE  VOICE 273 

CHAPTER   XIII 
FIRST  AID  IN  ACCIDENTS  AND  EMERGENCIES 280 

CHAPTER   XIV 

BACTERIA 305 

DISEASES  THAT  SPREAD  AND  DISINFECTANTS 312 

THE  CARE  OF  THE  SICK  ROOM 317 

APPENDIX: 
THE  STUDY  OF  PHYSIOLOGY  IN  ELEMENTARY  SCHOOLS     .    .    .  325 

GLOSSARY 331 

INDEX " 343 


EXPLANATION    OF    THE    FRONTISPIECE 

A  STUDY  IN  THE  ANATOMY  OF  THE  HUMAN  BODY 

(Intended  for  Reference  and  Review  Exercises.) 

Presenting  Important  Muscles,  Arteries,  Veins,  Nerves,  and  also-  a  Few  Organs  of 
the  Chest  and  Abdomen.     (Front  view.) 

The  frontispiece  is  a  representation  of  the  human  body.  The  skin  has 
been  removed.  The  bones  and  muscles  that  make  up  the  front  wall  of 
the  chest  and  the  muscles  and  fatty  tissue  that  compose  the  front  of  the 
abdomen  have  also  been  removed. 

On  the  left  side  of  the  figure  (except  chest  and  abdomen)  only  the  skin 
and  fascia  have  been  removed,  showing  the  large  veins  of  the  head  and  neck 
and  also  the  principal  superficial  veins  and  nerves  of  the  upper  and  lower 
limbs.  The  outline  of  the  tibia  is  also  shown. 

On  the  right  side  of  the  figure  (except  chest  and  abdomen)  a  few  large 
muscles  have  been  removed  from  the  limbs,  exposing  other  large  muscles 
and  also  important  arteries,  veins,  and  nerves.  The  arrangement  of  the 
fascia  about  both  knees  is  also  shown. 

1.  The  muscles  and  tendons  shown  in  the  figure  should  be  studied  in 
connection  with  the  text  of  Chapter  III.     Compare  muscles  and  tendons 
of  figure  with  those  shown  in  Figs.  38,  p.  49;  39,  p.  50;  40,  p.  51 ;  and 
42,  p.  52.     Note  the  display  of  tendons  on  right  forearm,  the  palm  of  right 
hand,  the  front  of  right  leg,  and  the  top  of  right  foot. 

2.  The   arteries,    represented  in  the  figure,  should  be  compared  with 
those  in  Figs.  83,  p.  135;  84,  p.  137;  85,  p.  139;  91,  p.  147;  92,  p.  149; 
97,  p.  156;  and  99,  p.  158. 

3.  Compare  the  veins  in  the  figure  with  Figs.  84,  p.  137,  and  96,  p.  155. 

4.  The  nerves  should  be  studied  in  connection  with  the  text  of  Chapter  X. 
Compare  the  superficial  nerves  in  the  figure  with  those  shown  in  Figs.  142, 
p.  226 ;   143,  p.  227  ;   145,  p.  231  ;   146,  p.  232  ;   147,  p.  235  ;  and  148,  p.  237. 

5.  The  heart  and  lungs  and  their  great  vessels,  as  shown  in  the  thoracic 
cavity,  should  be    studied    in    connection   with  Chapters  VII  and  VIII. 
Compare  with  Figs.  83,  p.  135  ;  84^.137;  85^.139;  89^.145;  92^.149; 
100,  p.  162;  and  102,  p.  164. 

6.  In  the  abdominal  cavity,  as  shown  in  the  figure,  the  intestines  and 
various  organs  have  been  removed,  exposing  only  the  kidneys  and  great 
arterial,  venous,  and  nerve  trunks.   Compare  with  Figs.  84,  p.  137  ;  92,  p.  149 ; 
and  128,  p.  205. 

vii 


OUR   BODIES 
AND   HOW  WE   LIVE 

CHAPTER   I 
INTRODUCTION 

1.  The  Study  of  Physiology  in  Schools.     We  are  now 

to  begin  the  study  of  a  few  things  about  our  bodies  and 
how  we  live.  This  branch  of  our  school  work,  which  is 
commonly  called  physiology,  appeals  to  every  thoughtful 
young  person. 

The  reason  for  it  is  plain  enough,  for  it  is  the  study  of 
ourselves.  It  describes  the  several  parts  of  our  bodies 
and  tells  us  how  they  do  their  work  ;  it  aims  to  make 
clear  a  few  of  the  great  laws  of  health,  and  teaches  us  why 
and  how  we  should  obey  them. 

With  this  knowledge  we  may  hope  to  live  happier  and 
more  useful,  because  healthier,  lives. 

2.  The  Importance  of  the  Study.     What  study  could  be 
more  important,    more   interesting,  and  more  fascinating 
than  that  which  has  to  do  with  the  structure  and  welfare 
of  our  own  bodies  ! 

We  gaze  with  wonder  and  admiration  at  the  marvelous 
work  done  by  the  intricate  machines  made  by  man.  Well 


2  OUR   BODIES   AND   HOW  WE   LIVE 

we  may,  for  they  seem  endowed  with  life.  But  in  the 
human  body  we  find  not  simply  a  most  perfect  and  delicate 
machine,  but  one  endowed  with  life,  a  mind,  a  soul. 

Indeed,  the  longer  we  live,  the  more  we  study  and 
reflect,  the  more  we  shall  realize  the  great  fact  that  the 
all-wise  Creator,  in  his  goodness  and  wisdom,  has  provided 
us  with  bodies  which,  in  the  words  of  the  Psalmist,  are 
"fearfully  and  wonderfully  made." 

3.  Questions  often  asked  by  Thoughtful  Persons.     We 
must  indeed  be  very  dull  if  we  have  not  at  some  time  or 
other  in  our  lives  asked  ourselves  many  curious  questions 
about  "the  house  in  which  we  live." 

Why  are  we  warm  ?  How  are  we  able  to  move  our 
limbs  ?  How  often  does  the  heart  beat  ?  Why  do  we  feel 
warmer  after  running  or  exercising  with  dumb-bells  ? 

By  what  strange  magic  are  the  milk,  beefsteak,  and  eggs 
we  eat  changed  into  bone,  teeth,  and  muscle  ?  Why  does 
the  doctor  feel  our  pulse  and  put  a  thermometer  under  our 
tongue  when  we  are  ill  ?  Why  is  it  so  hard  to  see  for  a 
few  moments  after  coming  into  a  darkened  room  from  the 
sunlight? 

These  and  hundreds  of  other  questions,  both  curious 
and  important,  can  be  answered  by  those  who  have 
mastered  the  simple  principles  of  the  subject  as  told  you 
in  this  book. 

4.  Animals  are  in  Motion.     We  need  not  be  told  that 
some  part  of  our  bodies,  as  the  heart,  is  always  in  motion. 
Even  in  sleep,  when  the  eyes,  the  hands,  and  the  feet  may 
be  still,  the  rise  and  fall  of  the  chest  in  breathing  and 
the  beating  of  the  heart  never  stop. 

We  also  know  that  we  can  move  from  one  place  to 
another.  We  need  not  wait,  like  the  trees  in  the  woods, 


INTRODUCTION  3 

for  the  wind  to  blow  us  to  and  fro,  or,  like  the  pebbles  by 
the  roadside,  for  somebody  to  move  us.  When  we  choose, 
we  can  move  from  place  to  place. 

Indeed,  it  is  true  that  every  living  animal,  even  the 
tiniest  creature  that  lives  its  brief  life  in  a  single  day  and 
can  be  seen  only  with  the  help  of  the  microscope,  has  the 
power  to  move  of  itself. 

5.  Animals  are  Warm.     Even  in  the  coldest  day  of  mid- 
winter, when  the  stones  and  trees  are  as  cold  as  ice,  our 
bodies,  except  perhaps  the  tips  of  the  fingers,  the  toes, 
and  the  ears,   are  always  warm.      On  a  winter  day  we 
sometimes  put  our  cold  fingers  to  the  lips  to  warm  them 
with  our  breath. 

In  fact,  the  bodies  of  all  animals  are  more  or  less  warm 
so  long  as  they  are  alive.  On  a  wintry  day  we  have  all 
seen  the  clouds  of  steam  blown  from  the  nostrils  and  rising 
from  the  warm  body  of  a  hard-working  horse. 

6.  The  Body  compared  to  a  Locomotive.     The  body  is,  in 
some  respects,  like  a  locomotive.     The  bones  and  muscles 
correspond  to  the  machinery,  and  the  food  we  eat  to  the 
fuel  that  is  used  in  running  it.     When  the  engine  is  to 
be  used,  the  fireman  puts  fuel  into  the  furnace,  and  soon 
the  water  in  the  boiler  is  heated  and  expands  into  steam. 
The  piston  begins  to  work.     This  moves  the  connecting 
rods  and  wheels.     And  so  the  locomotive  is  set  going  by 
means  of  the  fuel  which  was  put  into  the  furnace. 

Something  not  unlike  the  action  of  the  locomotive  occurs 
in  our  bodies.  We  take  food,  and  it  passes  into  the  stomach. 
By  means  of  that  food  we  are  kept  warm,  muscular  force 
is  developed,  and  our  limbs  and  other  parts  are  made  to 
work,  just  as  the  parts  of  the  engine  are  set  in  motion  by 
means  of  the  fuel. 


4  OUR   BODIES   AND    HOW  WE   LIVE 

7.  The  Body  as  a  Self-Repairing  Machine.     The  human 
body  and  the  locomotive  are  alike  in  another  respect,  — 
both  are  all  the  time  wearing  out.     There  is  an  important 
difference,   however,   between  the  two.      The  locomotive 
when  badly  worn  must  be  taken  to  pieces  and  repaired  by 
the  machinist. 

The  human  body,  on  the  other  hand,  is  constantly  repair- 
ing itself.  We  take  food  not  only  to  warm  us  and  to  give 
us  muscular  force,  but  also  for  the  building  up  and  repairing 
of  our  bodies. 

Remember,  then,  that  the  body  far  surpasses  the  engine 
in  the  perfection  of  its  mechanism,  inasmuch  as  it  is  a 
self -repairing  machine. 

CHEMICAL   COMPOSITION   OF   THE   BODY 

8.  Chemical  Elements  in  the  Body.     There  are  about 
seventy  different  substances  which,  when  pure,  cannot  be 
broken  into  any  simpler  forms  of  matter.     These  are  called 
elements. 

The  greater  number  of  substances  we  see  around  us  are 
compounded  of  two  or  more  elements.  These  compounds 
may  be  broken  up  into  simple  elements  by  heat,  and  by 
various  other  means. 

Our  bodies  are  almost  entirely  composed  of  thirteen  of 
the  seventy  elements.  Among  these  are  oxygen,  hydrogen, 
nitrogen,  carbon,  and  iron. 

Oxygen,  hydrogen,  and  nitrogen,  which  are  gases  in 
their  uncombined  form,  make  up  three  fourths  of  the  weight 
of  the  whole  human  body. 

Carbon,  which  exists  in  an  impure  state  in  charcoal, 
forms  more  than  one  fifth  of  the  weight  of  the  body. 


INTRODUCTION  5 

We  must  keep  in  mind  that,  with  slight  exceptions,  none 
of  these  elements  exist  in  the  body  in  their  elementary 
form.  They  are  combined  in  various  proportions  to  make 
compounds  which,  as  a  rule,  do  not  resemble  the  elements 
of  which  they  are  made  up.  Thus,  oxygen  and  hydrogen 
unite  to  form  water,  and  water  forms  more  than  two  thirds 
of  the  weight  of  the  whole  body. 

9.  Organic  Compounds.     There   is  in  the  human  body 
a  series  of  compound  substances  which  require  the  agency 
of  living  structures  for  their  formation.     They  are  built  up 
from  the  elements  or  from  simple  mineral  compounds  by 
plants,  and  are  called  organic  compounds. 

Animals  take  as  many  of  these  organic  substances  as 
they  require  and  build  them  up  into  the  materials  of  their 
own.  bodies,  which  process  often  results  in  the  formation  of 
still  more  highly  organized  forms. 

10.  The  Three  Great  Classes  of  Organic  Compounds.     The 
principal  organic  compounds  found  in  the  body  or  in  our 
food  are  usually  divided  into  three  great  classes  :  (i)  proteids 
(albuminous  substances),  (2)  carbohydrates  (starches,  sugars, 
and  gums),  (3)  fats. 

The  proteids,  the  type  of  which  is  egg  albumin,  or  the 
white  of  egg,  are  found  in  muscle  and  nerve,  in  glands,  in 
blood,  and  in  nearly  all  the  fluids  of  the  body. 

NOTE.  —  The  proteids,  because  they  contain  the  element  nitrogen 
while  the  others  mentioned  above  do  not,  are  frequently  called 
nitrogenous,  and  the  other  two  are  known  as  non-nitrogenous 
substances. 

The  extent  to  which  these  three  great  classes  of  organic  materials 
of  the  body  exist  in  the  animal  and  vegetable  kingdoms,  and  are  util- 
ized for  the  food  of  man,  will  be  described  in  the  chapter  on  food 
(Chapter  IV). 


6  OUR   BODIES   AND   HOW  WE   LIVE 

The  carbohydrates  are  formed  of  carbon,  hydrogen,  and 
oxygen,  the  last  two  in  the  proportion  to  form  water.  Thus, 
we  have  animal  starch,  or  glycogen,  stored  up  in  the  liver. 
Sugar,  as  grape  sugar,  is  also  found  in  the  body. 

The  fats  contain  the  same  three  elements  as  the  carbo- 
hydrates, but  in  quite  different  proportions.  There  are 
three  chief  fats  present  in  the  body. 

11.  Inorganic  Salts.     A  large  number  of  the  elements 
unite    one    with    another    to   form   inorganic    salts.     Thus, 
sodium  and  chlorine  unite  to  form  common  salt,  which  is 
found  in  many  of  the  tissues  and  fluids  of  the  body. 

Again,  certain  compounds  of  lime  and  soda  make  up 
more  than  half  the  material  of  the  bones. 

Compounds  of  iron  are  also  found  in  small  quantities 
in  the  coloring  matter  of  the  blood,  in  the  ash  of  bones,  in 
muscles,  and  in  other  tissues. 

CELLS    AND    PROTOPLASM 

12.  Cells.     All  living  things,  whether  plants  or  animals, 
are  made  up  either  of  a  single  cell  or  of  countless  numbers 
of  cells. 

The  human  body  is  built  up  of  these  minute  structures 
known  as  cells  and  the  things  which  the  cells  have  made. 
These  cells  are  so  small  that  we  must  use  a  powerful  micro- 
scope to  see  them  at  all. 

In  a  general  way  we  may  describe  a  cell  as  a  tiny 
mass  of  jelly  in  which  floats  another  still  smaller  mass 
of  slightly  different  composition,  called  the  nucleus  of  the 
larger  one. 

Cells  are  of  various  shapes  and  sizes,  spherical,  flat,  and 
threadlike.  Thus,  we  .shall  learn  in  a  succeeding  chapter 


INTRODUCTION 


about  the  rounded  cells,  or  corpuscles,  which  float  in  the 
blood,  and  of  the  flattened  cells  which  can  be  scraped  from 
the  tongue. 

13.  Variety  of  Work  done  by  Cells.     Some  cells  can 
change  their  forms,  as  those  of  muscle ;  other  cells  make 
fluids  which  help  us  to  digest  our  food.     The  outer  layer 
of  cells,  known  as  the  skin,  forms  a  protective  coat  to  the 
body.  The  liver  cells  manufacture 

or  secrete  the  bile,  and  the  bone 
cells  help  to  make  the  bones. 

Millions  of  blood  cells  do  their 
work  and  perish  every  day,  while 
the  brain  cells  act  in  some  mysteri- 
ous way  to  help  us  to  think. 

In  short,  our  very  life  exists  in 
the  cell. 

14.  Cell  Life  as   Shown   by  the 

Amoeba.  The  work  done  by  cells 
is  well  shown  in  the  life  history  of  the  amoeba,  a  tiny  creature 
not  more  than  ^-^  of  an  inch  in  diameter  and  found  in 
water  containing  decaying  matter. 

If  we  use  a  microscope  powerful  enough  to  magnify  a 
pin's  head  into  the  size  of  a  bicycle  wheel,  we  find  that 
this  bit  of  life  appears  as  a  mass  of  jelly  like  substance 
with  little  grains  within  it.  This  jelly  is  known  as  proto- 
plasm, meaning  the  primitive  or  first  stuff.  Within  the 
amoeba  may  sometimes  be  seen  a  round  spot  known  as 
the  nucleus. 

With  the  aid  of  the  microscope  the  life  of  the  amoeba, 
as  it  is  lived  in  a  drop  of  water,  can  be  studied.  It  creeps 
about,  it  changes  its  shape,  it  selects  and  digests  its  food, 
it  breathes  in  oxygen  from  the  air  in  the  water  and 


FIG.  i.     Diagram  of  a  Cell. 

4,  cell  wall ;  B,  nucleus ;  C,  nucle- 
olus ;  D,  protoplasm  of  cell  body. 


OUR   BODIES   AND   HOW   WE   LIVE 


gives  forth  waste  material.  When  the  amoeba  grows  to 
a  certain  size  it  divides  into  two  parts,  each  of  which 

becomes  an  amoeba  in  itself.  In 
every  drop  of  our  blood  certain 
cells,  the  white  blood  corpuscles, 
may  be  found,  even  smaller  than 
the  amoeba  and  not  unlike  it  in 
structure. 

15.  The  Nature  of  Protoplasm. 
Besides  proteid,  and  usually  a  small 
amount  of  carbohydrates  and  fat, 
protoplasm  contains  much  water  in 
which  are  dissolved  small  quanti- 
ties of  mineral  substances.     Our 
bodies,  as  we  have  just  learned,  are 
made  up  of  exactly  these  same  sub- 
stances,—  proteids,  carbohydrates, 
fats,  water,  and  mineral  salts.  They 
are  contained  in  the  protoplasm,  or 
living  matter. 

Finally,  we  must  remember  that 
to  manifest  life,  protoplasm,  the 
essential  material  of  all  living  things, 
whether  plants  or  animals,  must 
come  in  contact  with  oxygen  and 
water  and  must  be  warmed  to  a 
certain  temperature. 

16.  How  Energy  is  set  Free  by 
Protoplasm.     Coal,  as  we  know,  is 

the  hardened  vegetable  deposit  of  forests  that  lived  and 
died  in  past  ages.  If  we  set  fire  to  coal,  its  energy  is  set 
free  or  awakened  from  its  long  rest  like  the  sleeping  princess 


FIG.  2.  Diagram  showing  an 
Amoeba  in  Successive 
Stages  of  Division. 

The  dark  spot  is  the  nucleus. 
The  light  and  somewhat 
rounded  clear  spots  are  more 
or  less  sharply  denned  cavities 
filled  with  fluid,  and  are  known 
as  vacuoles. 


INTRODUCTION 


FIG.  3.     Various  Forms  of  Cells. 


in  the  fairy  tale.  We  can  use  this  energy  to  produce  light, 
heat,  or  electricity,  or  to  do  work. 

In  other  words,  energy,  originally  derived  from  the  sun, 
was  stored  up  in  the  coal  and  hidden  for  countless  years 
until  changed  by  burning  into  the  energy  of  heat,  move- 
ment, light,  and  electricity. 

So  it  is  with  the  warm,  living,  wet  protoplasm  of  our 
bodies,  in  the  presence  of  oxygen.  It  is  ever  being  burnt 
or  broken  up  into  simpler 
compounds.  The  energy 
thus  released  may  show 
itself  as  heat  or  motion. 
It  is  for  this  reason  that 
our  bodies  are  warm  and 

,  ,  .  A,  columnar  cells  found  lining  various  parts 

that  we  nave  tne  power  of  the  intestines  (called  columnar  efithe- 
of  movement.  Hum);  S,  cells  of  a  fusiform  or  spindle 

shape  found  in  the  loose  tissue  under  the 
skin  and  in  other  parts  (called  connective- 

Experiment  i .    To  examine  tissue  cells}.  c^  cell  having  many  processes 

a    typical   nucleated  cell.       A  or  projections  —  such  are  found  in  some 

colorless  human  blood  corpus-  kinds  of  connective  tissue;  D,  primitive 

cle  is  a  typical  nucleated  cell.  cells  composed  of  protoplasm  with  nucleus, 

J  and  having  no  cell  wall.     All  are  repre- 

Wind  a  piece  of  twine  tightly  sented  about  400  times  their  real  size. 

around  the  last  joint  of  a  finger. 

Prick  the  skin  with  a  clean  needle.  A  drop  of  blood  will  flow.  Dilute 
it  with  a  drop  of  water,  or  still  better,  with  a  few  drops  of  very  dilute 
acetic  acid.  Spread  the  diluted  blood  on  a  piece  of  glass  and  put 
under  a  cover  glass.  Examine  with  a  compound  microscope. 

A  large  number  of  red  corpuscles  may  be  seen  and  with  some 
patience  one  or  more  colorless  cells.  An  internal  rounded  body  in 
the  colorless  cells  may  become  visible,  which  is  the  nucleus! 

1  Place  a  drop  of  carmine  fluid  on  the  slide  close  to  the  edge  of  the 
cover  glass  and  press  a  piece  of  blotting  paper  against  the  opposite  edge 
to  absorb  a  little  of  the  liquid.  When  the  blood  under  the  microscope 
is  thus  stained  with  carmine  fluid,  the  nucleus  is  generally  more  deeply 
stained  than  the  rest  of  the  corpuscle. 


10 


OUR  BODIES   AND    HOW  WE   LIVE 


m   - 


THE  PRINCIPAL  TISSUES  OF  THE  BODY 

17.  The  Tissues  of  the  Body.  A  house,  as  we  all  know, 
is  built  of  timbers,  bricks,  stone,  cement,  glass,  iron,  and 
other  material,  properly  arranged  and  adjusted  to  endure 
wear  and  tear,  as  well  as  for  the  convenience  and  comfort 

of  its  occupant. 

In  a  general  way  we  may 
say  that  our  bodily  houses  are 
built  of  cells  of  various  sizes 
and  shapes,  arranged  in 
groups.  These  sets  of  cells 
compose  the  tissues  or  mate- 
rials, and  each  tissue  is  distrib- 
uted through  different  parts 
of  the  body  in  order  to  do  its 
special  work. 

In  following  chapters  we 
shall  learn  of  two  of  the  most 
important  of  these  tissues,  the 


FIG.  4.     Various  Kinds  of 
Epithelial  Cells. 


(Copter  X)  and  the 

ciliated  conical  cells  of  the  trachea;      mUSCUlar     (Chapter     III),— 

-YS2!  F,    the  «  master  tissues,"  so  called 

squamous  cell  of  the  cavity  of  the     because    it    is    by    them     that 

the   active   life  of   the    indi- 


mouth,  seen   on   its    broad   surface; 
G,  squamous  cell,  seen  edgeways. 


vidual  is  carried  on. 

In  the  next  chapter,  the  osseous  tissue,  or  bone,  will  be 
described. 

18.  The  Epithelial  Tissues.  One  of  the  simplest  of  the 
tissues  in  the  body  is  called  epithelium,  and  its  cells  are  called 
epithelial  cells.  It  serves  as  a  lining  of  various  cavities, 


INTRODUCTION 


II 


a  covering  for  the  surface  of  the  body,  and  the  essential  part 
of  various  organs  called  glands. 

There  are  several  varieties  of  this  tissue.  Thus,  we 
have  the  flat  cells  of  the  outer  skin  and  the  lining  of  the 
mouth,  the  pear-shaped  cells  in  the 
lining  of  the  stomach  and  the  intes- 
tines, and  cells  with  fine,  threadlike 
fringes,  called  cilia,  found  in  the  lining 
of  the  air  passages  (Sec.  225). 

Experiment  2.  To  examine  one  form  of 
epithelium  (squamous}.  Gently  scrape  the 
inside  of  the  lips  or  cheek  with  an  ivory 
paper  knife.  Place  a  tiny  portion  of  the 
substance  thus  obtained  upon  a  glass  slide. 
Cover  it  with  a  thin' cover  glass,  and  if  neces- 
sary add  a  drop  of  water.  Examine  with 
the  microscope,  and  the  irregularly  formed 
(squamous,  or  pavement)  epithelial  cells 
may  be  seen. 

Experiment  3.  To  examine  another  form 
of  epithelium  (ciliated}.  With  the  back  of 
a  knife  blade  gently  scrape  a  little  of  the  FIG.  5. 
membrane  from  the  roof  of  a  frog's  mouth. 
Transfer  to  a  glass  slide  and  add  a  drop  of 
salt  solution.  Place  over  it  a  cover  glass 

with  a  hair  underneath  to  prevent  pressure  upon  the  cells.  Examine 
with  a  microscope  under  a  high  power.  The  cilia  move  quite  rapidly 
while  they  are  fresh  (Sec.  225). 


Cross-Section  of 
Epithelium  from  the 
CEsophagus. 


19.  The  Connective  Tissues.  Just  as  certain  cells  develop 
into  masses  of  cells  which  we  call  muscle,  brain,  and  skin, 
so  other  cells  are  set  apart  to  produce  tissues  by  which 
the  frame  of  the  body  and  its  organs  are  molded  and  held 
together.  They  are  called  connective  tissues.  They  form  a 


12 


OUR   BODIES   AND   HOW   WE   LIVE 


FIG.  6.     White  Fibrous  Tissue. 
Highly  magnified. 


sort  of  flexible  frame  for  the  body  and  may  be  said  to  serve 
as  packing,  binding,  or  supporting  tissues.  This  name 
includes  tissues  which  vary  greatly  in  their  appearance. 

20.  Connective  Tissues  with  White  and  Elastic  Fibers. 
If  we  take  a  bit  of  well-cooked  corned  beef  and  tease  it 

apart  with  a  needle,  we  shall 
find  something  that  looks 
like  the  fluff  of  cotton  wool. 
This  is  one  kind  of  connec- 
tive tissue.  Now,  if  we  look 
at  the  tiniest  fibrils  of  the 
beef  under  the  microscope, 
we  shall  see  wavy  bundles 
of  white  fibers  running  in  all 
directions.  These  are  known 
as  white  fibrous  tissue.  Across  these  bundles  run  other  fine 
fibers  which  branch  and  coil  up  like  a  broken  spring  and 
are  highly  elastic.  These  are  known  as  yellow  elastic  tissue. 
The  connective  tissue  with  white  fibers  sometimes  forms 
a  very  thin  sheet,  as  in  the  delicate 
covering  of  bone  known  as  the 
periosteum,  or  it  may  be  made  up 
into  ropelike  bands,  as  in  the  liga- 
ments of  joints  and  the  tendons 
of  muscles..  It  is  the  connective 
tissue  with  the  yellow  elastic  fibers 
which  makes  the  coats  of  the  arter- 
ies, and  certain  ligaments,  elastic. 

21.  Areolar  Tissue.     This  is  a 
form   of  connective  tissue  which 

makes  a  protective  covering  for  important  organs.  It  con- 
sists of  bundles  of  delicate  fibers  which  interlace  and  cross 


FIG.  7.     Yellow  Elastic 

Tissue. 
Highly  magnified. 


INTRODUCTION 


one  another,  forming  irregular  spaces  or  meshes.  These 
little  spaces,  in  health,  are  filled  with  fluid  that  has  oozed 
out  of  the  blood  vessels. 

22.  Fatty  Tissue.     The    connective    tissue   sometimes 
becomes  filled  with  fat.     It  is  then  called  fatty  or  adipose 
tissue.     The  fat  is  deposited  as  tiny  drops  of  oil  within  the 
tissue  cells.     The  fat  cells  are- 
then    bound  together   by  con- 
nective tissue  into  little  lumps, 

which  we  are  able  to  find  on 
picking  a  bit  of  suet  to  pieces. 
Fatty  tissue  is  usually  plen- 
tiful beneath  the  skin,  in  the 
marrow  of  bones,  on  the  surface 
of  the  heart,  and  in  many  other 
parts  of  the  body. 

23.  Cartilage  or  Gristle. 
Cartilage,  or  gristle,  is  a  form  of 
connective  tissue  which  under 
the  microscope  is  seen  to  consist 
of  a  matrix  or  base  in  which  cells 
are  imbedded,  either  singly  or 
in  groups.     It  is  tough,  flexible, 
and  highly  elastic.     Sometimes 
the  base  contains  a  network  of 
white  or  elastic  fibers. 

24.  Some  Technical  Words  explained.     It  is  plain  that  a 
watchmaker  would  not  be  able  to  understand  the  working 
of  a  watch  unless  he  first  made  himself  acquainted  with  its 
various  parts.     So  it  is  with  the  study  of  our  bodies.     We 
must  know  something  about  their  structure  before  we  can 
understand  how  they  act  and  move,  or,  in  one  word,  live. 


Connective  Tissue  from 
a  Lymphatic  Gland. 

Consisting  of  a  very  fine  network  of 
fibrils,  around  which  are  cells  of 
various  sizes. 


OUR   BODIES   AND    HOW   WE   LIVE 


The  science  which  tells  us  about  the  structure,  form,  and 
position  of  the  different  parts  of  the  body  is  called  anatomy.1 
Take  the  stomach  for  an  illustration.  If  we  learn  what 
it  is,  where  it  is,  how  it  looks,  its  shape, 
size,  and  general  appearance,  this  is  its 
anatomy. 

The  science  which  explains  the  uses 
or  functions  of  the  different  parts  of 
the  body  is  called  physiology. 

If  we  learn  for  what  special  purpose 
the  stomach  is  made,  just  what  its  differ- 
ent parts  do,  and  how  they  do  it,  this 
is  its  physiology. 

Now,  if  we  would  learn  how  to  take 
care  of  the  different  parts  of  the  body 
and  how  to  keep  them  in  good  health, 
we  may  do  this  by  the  study  of  hygiene,2 
or  the  science  which  tells  us  about 
health. 

An  organ  is  a  part  of  the  body  which 


FIG.  9.     Longitudinal 
Section  of  Cartilage. 


Magnified  about 

650  times. 

Showing  (i)  cartilage 
with  matrix  and  cells; 
(2)cartilage  with  matrix 

containing  ceils  and    does  a  special  work.     Thus,  the  eye  is 

white  fibers.  f     .    .  .     _.  f  ,,      , 

an  organ  of  sight,  the  nose  of  smell,  the 
stomach  of  digestion,  and  the  lungs  of  breathing. 

The  special  work  which  an  organ  has  to  do  is  said  to 
be  the  function  or  use  of  that  organ ;  thus,  it  is  the  function 
of  the  eye  to  see,  and  of  the  liver  to  secrete  bile. 

1  The  word  "  anatomy  "  comes  from  two  Greek  words  meaning  a  cut- 
ting through,  or  dissection,  that  is,  the  act  of  cutting  an  animal  in  pieces 
for  the  purpose  of  study. 

2  The  word  "  hygiene  "  is  derived  from  the  name  of  the  Greek  goddess 
Hygeia,  who  is  said  to  have  watched  over  the  health  of  the  people. 


INTRODUCTION  15 


QUESTIONS  ON  THE  TEXT 

I.  What  branch  of  school  work  are  we  now  to  study?     2.  Why 
does  this  study  appeal  to  every  thoughtful  young  person?     3.  What 
can  you  say  about  the  importance  of  the  study  ?     4.  What  great  fact 
should  we  realize  ?     5.  What  questions  naturally  suggest  themselves 
to  thoughtful  persons?     6.   Is  some  part  of  our  bodies  always  in 
motion?     7.  What  power  has  every  living  animal?     8.  How  do  you 
know  that  all  living  animals  are  more  or  less  warm?     9.  How  does 
the  body  resemble  a  locomotive  ?     10.  Can  you  tell  where  the  com- 
parison fails  ? 

II.  Of    how   many    chemical    elements    is   the    body   composed? 
12.   Mention  five  of  the  more  important  elements.     13.  What  is  meant 
by  organic  compounds  ?     14.  What  are  the   three  great  classes  of 
organic  compounds?     15.  What  is  meant  by  the  proteids?     16.  Of 
what  are  the  carbohydrates  formed  ?     17.  What  can  you  say  of  the 
amount  of  fat  in  the  body?     18.  What  is  meant  by  the  inorganic 
salts?     Illustrate.     19.  Of  what  are  all  living  plants  and  animals 
made  up  ?     20.  How  will  you  define  a  cell  ? 

21.  What  variety  of  work  is  done  by  cells  ?  22.  What  is  an  amoeba  ? 
23.  What  can  be  seen  of  the  life  of  the  amoeba  with  the  aid  of  the 
microscope?  24.  Of  what  is  protoplasm  composed?  25.  How  is 
energy  set  free  by  protoplasm  ?  26.  To  what  may  we  roughly  com- 
pare the  tissues  of  the  body?  27.  What  are  called  the  two  "master 
tissues"?  28.  What  can  you  say  about  the  epithelial  tissues  ?  29.  What 
general  purpose  do  the  connective  tissues  serve  ? 

30.  What  is  meant  by  white  fibrous  tissue?  31.  What  is  yellow 
elastic  tissue?  32.  Of  what  use  are  these  two  kinds  of  connective 
tissues?  33.  Describe  areolar  tissue  and  explain  its  use. 

34.  Describe  fatty  tissue  and  state  where  it  is  found.  35.  What 
is  meant  by  cartilage,  or  gristle  ?  36.  What  is  meant  by  anatomy  ? 
physiology  ?  hygiene  ?  37.  Give  one  illustration  to  make  plain  each 
word.  38.  What  is  an  organ?  Illustrate.  39.  What  is  meant  by  the 
function  of  an  organ  ?  Illustrate. 


CHAPTER  II 
THE    BONY   FRAMEWORK 

5.  The  Skeleton.  Every  animal  must  have  some  kind 
of  framework  or  support  to  give  its  body  form  or  shape. 
This  framework  in  most  animals  is  chiefly  made  up  of  bones. 

This  bony  support  is  called  the  skeleton,  meaning  a  dried 
body.  It  is  to  the  body  what  the  ribs  are  to  a  ship,  or 
what  the  frame  is  to  a  house. 

Every  one  is  familiar  with  the  picture  of  the  human 
skeleton.  It  shows  us  how  the  bones  look  when  properly 
prepared  and  held  in  place  by  wires.  There  are  in  all  two 
hundred  and  six  separate  bones  in  the  adult  skeleton.  The 
teeth  are  not  bones,  but  are  a  part  of  the  skin. 

The  bones  give  firmness,  strength,  and  protection  to 
the  soft  tissues  and  vital  organs,  and  form,  as  it  were,  the 
foundation  upon  which  our  bodies  are  built. 

26.  How  Bone  is  made  up.  Bone  is  a  hard  and  strong 
substance,  made  up  of  animal  matter  united  with  certain 
mineral  earths,  chiefly  compounds  of  lime.  The  earthy 
part  of  bone  makes  up  about  two  thirds  of  its  weight,  and 
the  animal  portion  the  other  third.  The  lime  gives  hard- 
ness and  firmness  to  the  bones,  while  the  animal  substance 
makes  them  elastic,  tough,  and  flexible. 

In  childhood  the  bones  have  more  animal  matter  than 
those  of  the  adult ;  hence  a  child's  bones  do  not  break 
easily,  and,  when  broken,  soon  knit  together. 

16 


THE   BONY   FRAMEWORK 


FIG.  10.     The  Skeleton. 


18  OUR   BODIES   AND   HOW   WE   LIVE 

In  old  age  there  is  more  lime  in  the  bones  in  proportion 
to  the  animal  matter ;  hence  they  are  more  brittle  and 
more  easily  broken  than  in  early  life.  If  broken  they  unite 
quite  slowly,  or  not  at  all. 

Experiment  4.  To  show  the  earthy  or  mineral  part  of  bone.  Put 
a  large  soup  bone  on  a  hot,  clear  fire  until  it  is  at  a  red  heat.  At 
first  it  becomes  black,  but  after  a  time  it  turns  white. 

Examine  the  bone  after  it  is  cool.  The  animal  matter  has  now 
been  burnt  out,  leaving  the  earthy  or  mineral  part,  a  white,  brittle 
substance  showing  every  outline  of  the  bone. 

Experiment  5.  To  show  the  animal  part 
of  bone.  Scrape  and  clean  a  chicken's  leg 
bone,  part  of  a  sheep's  rib,  or  any  other  small, 
slender  bone.  Add  one  fourth  of  a  cupful  of 
muriatic  acid  to  a  quart  of  water  and  place 
the  mixture  in  a  wide-mouthed  bottle  or  glass 
fruit  jar.  Soak  the  bone  .in  the  acid  mixture 
for  a  few  days,  adding  a  little  more  acid  from 
time  to  time. 

FIG.  ii.     The  Fibula  The  mineral  matter  is  slowly  dissolved,  and 

tied  into  a  Knot      t^e  bone>  although  retaining  its  original  form, 
Bftcr  Ae  Mincr?1     becomes  so  soft  as  to  be  readily  cut.     If  the 

experiment  be  carefully  performed,  the  bone 
solved  by  Acid. 

may  even  be  tied  into  a  knot. 

27.  General  Structure  of  the  Bones.  Take  a  long  bone, 
like  that  from  a  sheep's  leg  or  even  a  part  of  a  beef  shin 
bone,  and  saw  it  lengthwise.  Note  that  the  ends  are  soft 
and  spongy,  while  the  shaft  is  hard  and  compact.  The 
central  cavity  runs  almost  the  whole  length  of  the  bone. 
It  is  filled,  in  life,  with  a  soft,  fatty  substance  called  marrow. 

If  the  bones  were  solid,  they  would  be  much  too  heavy 
for  ordinary  use.  A  bone  may  be  hard  as  a  rock  on  the 
outside,  on  account  of  its  thin,  dense  layer  of  compact 
bony  tissue,  and  yet  be  light  because  of  its  cavity  and  the 
trellis  work  of  loose,  spongy  texture  at  the  ends. 


THE    BONY   FRAMEWORK 


A  cylindrical  bone  is  not  weak  although  it  is  hollow.  The 
pillars  of  steel  bridges,  the  posts  for  the  support  of  electric 
wires,  and  the  frame  of  a  bicycle  are 
made  of  hollow  steel  tubes.  We  all 
know  that  stalks  of  grass  and  grain  are 
so  light  and  slender  that  they  will  bend 
before  a  light  breeze,  and  yet  they  are 
strong  enough  to  bear  their  load  of  seed. 

Experiment  6.  Saw  in  two,  lengthwise,  a 
part  of  a  beef  shin  bone,  or  a  portion  of  a 
sheep's  or  a  calf's  leg,  including,  if  convenient, 
the  kneejoint.  Boil,  scrape,  and  carefully  clean 
one  half.  Note  the  compact  and  spongy  bone, 
the  shaft,  etc. 

Experiment  7.  After  the  flesh  has  been  cut 
from  the  second  half,  note  the  pinkish  white 
appearance  of  the  bone,  the  marrow,  etc.  Knead 
a  small  piece  of  the  marrow  in  the  palm  ;  note 
its  oily  appearance.  Contrast  this  fresh  bone 
with  an  old,  dry  one  picked  up  in  the  field. 

NOTE.  —  While  waiting  for  class  use,  fresh 
bones  should  be  kept  in  a  cool  place,  carefully 
wrapped  in  cloths  moistened  with  listerine,  dilute 
carbolic  acid  solution,  or  even  glycerin  solution, 
—  an  ounce  to  one  pint  of  water. 

28.  The  Shape  of  Bones.  Bones  are 
of  many  different  shapes,  according  to 
the  uses  to  which  they  are  put.  Some 
are  long,  with  hollow  shafts,  as  the  bones 
of  the  arm  and  the  leg;  others  are  short 
or  irregular,  to  give  strength,  as  the  bones  of  the  fingers, 
the  toes,  and  the  spine. 

Some  bones  are  flat,  for  protection  and  to  cover  cavities, 
like  the  bones  of  the  skull  and  shoulder  blades  ;  while  others 


FIG.  12.  The  Right 
Femur  sawed  in 
Two  Lengthwise. 

Showing  arrangement 
of  compact  and 
spongy  tissue. 


20 


OUR   BODIES   AND   HOW   WE   LIVE 


FIG.  13.     Cross-Section  from 
Shaft  of  a  Long  Bone. 

Magnified  56  times. 

Little  openings  (Haversian  canals) 
are  seen,  and  around  them  are 
arranged  rings  of  bone  with  lit- 
tle dark  spaces  (lacuncs),  from 
which  branch  out  fine  dark  lines 
(canalictilf). 


are  of  various  odd  shapes  and  sizes, 
and  hence  are  called  irregular,  as 
the  bones  of  the  wrist,  the  skull, 
and  the  ankle. 

29.  How  Bone  looks  under  the  Mi- 
croscope. Bones  have  a  great  number 
of  very  small  blood  vessels,  which 
pass  through  tiny  canals,  Haversian 
canals,  in  the  bones,  carrying  mate- 
rials for  their  nourishment  and 
growth.  Round  these  canals  the 
spiderlike  bone  cells  lie  in  small  cav- 
ities, lacunae,  which  are  arranged  in 
circles  or  rows.  These  cavities  are 
joined  to  one  another  and  to  the 
canal  which  they  surround,  by  other 
extremely  fine  canals,  canaliculi.  The 
nourishing  fluid  of  the  blood,  lymph, 
soaks  through  these  minute  cavities 
to  all  parts  of  the  bone. 

The  hard  part  of  the  bone  lies 
around  the  Haversian  canals  in  lay- 
ers, lamellae,  which  are  interrupted  at 
intervals  by  the  lacunas  and  canaliculi. 

When  a  thin  section  of  hard,  dry 
bone  is  examined  under  the  micro- 
scope, the  Haversian  canals  are  seen 
as  holes  surrounded  by  lamellae  of 
bone.  The  lacunae  and  canaliculi, 
filled  with  dust  and  air,  appear  as 
dots  and  lines.  The  bone  cells  and 
marrow  have  entirely  disappeared. 

NOTE.  —  A  very  delicate  layer  of 
connective  tissue,  called  the  periosteum, 
closely  adheres  to  every  part  of  the 


THE   BONY   FRAMEWORK 


21 


bones,  except  at  the  joints,  where  it  is  protected  with  cartilage. 
Shreds  of  the  periosteum  may  be  stripped  off  with  forceps,  if  the 
bone  is  soaked  for  some  time  in  water.  This  membrane  plays  a 
very  important  part  in  the  formation,  growth,  and  repair  of  bones, 
as  the  blood  vessels  of  bones  form  a  network  in  them  before  entering 
the  Haversian  canals.  It  is  therefore  of  great  surgical  importance. 
Bones  have  been  removed,  leaving  the  periosteum,  within  which 
remarkable  tissue  the  entire  bone  has  grown  again. 


THE   BONES   OF   THE   HEAD 

30.  The  Skeleton  and  its  Three  Main  Divisions.     The 
skeleton,  or  bony  framework  of  the  "house   we  live  in," 
consists  of  the  bones  of  the  head, 

the  trunk,  and  the  limbs. 

31.  The  Bones  of  the  Head. 
The  bones  of  the  head  are  usu- 
ally described  in  two  parts,— 
those  of  the  cranium  and  those 
of  the  face.    Together  they  form 
the  skull. 

The  general  shape  of  the 
head  is  that  of  an  arch.  The 
arch  is  the  strongest  shape  in 
which  the  skull  could  be  made, 
just  as  the  arched  bridge  is  the 
strongest  shaped  bridge  which 
can  be  made  to  bear  the  heavy 
loads  that  pass  over  it. 

32.  The   Bones  of  the   Cra- 
nium.      The    greater   part    of 

the  skull   consists   of  a   rounded,   bony  box,   the   cranium, 
which  holds  and  protects  the  brain  under  its  domelike  roof. 


FIG.  14.  The  Skull.  (Front  view.) 

A,  frontal  bone;  B,  parietal  bone; 
C,  temporal  bone ;  D,  sphenoid 
bone  ;  £,  malar  bone ;  F,  upper 
jawbone ;  G,  lower  jawbone. 


22  OUR  BODIES   AND   HOW   WE   LIVE 

It  is  made  up  of  eight  bones  closely  locked  together  by  seams, 
or  sutures,  somewhat  like  the  dovetailing  used  by  carpenters. 
These  eight  bones  are  : 

1  Frontal  (forehead)  i  Occipital  (back  of  head) 

2  Parietal  (side  of  head)  i  Sphenoid  (wedge-shaped) 
2  Temporal  (temples)                  i  Ethmoid  (sievelike). 

The  frontal  bone  forms  the  forehead. 

The  parietal  bones  form  part  of  the  side  walls,  top,  and 
back  of  the  skull. 

The  temporal  bones  lie  round  each  ear  and  form  the 
temples  on  either  side. 

The  occipital  bone  forms  the  lower  part  of  the  back  of  the 
skull.  This  broad,  thin  bone  rests  on  the  topmost  bone 
of  the  backbone,  and  is  pierced  by  a  large  oval  opening 
where  the  spinal  cord  joins  the  brain. 

The  sphenoid,  or  wedge  bone,  is  wedged  in  between  the 
bones  of  the  cranium  and  those  of  the  face,  and  serves  to 
lock  together  fourteen  bones. 

The  ethmoid,  or  sievelike  bone,  so  called  because  it  is  full 
of  holes  like  a  sieve,  lies  in  the  base  of  the  skull  between 
and  above  the  eye  cavities  just  at  the  root  of  the  nose. 

33.  The  Bones  of  the  Face.     All  bones  of  the  face,  except 
the  lower  jawbone,  are  firmly  fixed  to  each  other  and  to 
the  bones  of  the  cranium. 

The  face  contains  fourteen  bones,  viz. : 

2  Malar,  or  cheek  bones  2  Palate  bones 

2  Nasal,  or  nose  bones  2  Lachrymal  bones 

2  Upper  maxillary,  or  upper  jawbones  i  Vomer,  or  plowshare  bone 

i  Lower  maxillary,  or  lower  jawbone  2  Turbinated,  or  spongy  bones. 

34.  The  Larger  Bones  of  the  Face.     Under  the  orbits 
are  the  two  malar,  or  cheek  bones.     Some  races  have  much 


THE    BONY   FRAMEWORK 


higher  cheek  bones  than  others.  Indeed,  some  races,  like 
the  American  Indians,  are  recognized  by  the  peculiarity 
in  the  size  and  shape  of  their  cheek  bones. 

The  two  nasal  bones  form  the  hard  part,  or  bridge,  of 
the  nose. 

The  two  upper  jawbones  form  a  part  of  the  roof  of  the 
mouth  and  the  floors  of  the  orbits.  In  them  is  fixed  the 
upper  set  of  teeth. 

The  lower  set  of 
teeth  is  fixed  in 
the  lower  jawbone, 
which  moves  by 
means  of  a  hinge 
joint,  thus  allowing 
the  opening  and 
shutting  of  the 
mouth. 

35.  The  Smaller 
Bones  of  the  Face. 
The  remaining 
bones  of  the  face 
are  small.  Two 
bones,  forming  the 
back  part  of  the 
roof  of  the  mouth, 
are  called  the  palate  bones.  Sometimes  infants  are  born 
with  a  "cleft  palate."  This  means  that  the  two  palate 
bones  have  not  been  joined  together. 

Two  little  bones,  made  like  little  troughs,  carry  the  tears 
from  the  eyes  to  the  nose.  They  are  in  shape  somewhat 
like  the  finger  nails,  and  are  called  the  lachrymal  bones, 
from  a  Latin  word  meaning  tear. 


FIG.  15.     The  Skull.     (Side  view.) 

A,  upper  jawbone ;  £,  malar  bone ;  C,  nasal  bone ; 
D,  lower  jawbone  ;  £,  frontal  bone ;  f,  right  pari- 
etal bone  ;  G,  occipital  bone ;  //,  temporal  bone ; 
K,  sphenoid  bone. 


OUR  BODIES   AND   HOW  WE    LIVE 


The  vomer,  or  plowshare  bone,  so  called  from  its  resem- 
blance to  the  share  of  the  farmer's  plow,  is  situated 
between  the  nostrils. 

Two  little  scroll-like  bones  within  the  nose  cavity  are 
known  as  the  twisted  or  turbinated  bones. 

36.    How  the  Bones  of  the  Head  are  joined  together.    The 

bones  of  the  head  are  joined 
together  in  a  peculiar  way. 
Each  bone  has  uneven  edges, 
somewhat  like  the  teeth  of  a 
saw,  which  fit  into  the  edges  of 
the  bone  to  which  it  is  joined. 
In  adults  these  edges  fit  into 
each  other  and  grow  together, 
resembling  the  dovetailed  joints 
in  a  cabinetmaker's  work.  They 
are  called  sutures,  from  a  Latin 
word  which  means  a  sewing  or 
a  seam. 

In  infancy  some  of  the  bones 
of  the  skull  do  not  meet,  and 
FIG.  16.    The  Base  of  the  Skull.  the  throbbing  of  the  brain  be- 

A,  palate  process  of  upper  jawbone ;  neath   them    at    the    top    of    the 
.5.  zygoma,  forming  zygomatic arch;  ,      ,.•,  ,         1111-  r 

C,  condyle,  for  forming  articulation  head,     like    the    bubbling    of     a 

with  atlas;    D,  foramen  magnum;  Sprma-     is    easily    SCCll.       These 
£,  occipital  bone.  °  J 

openings  are  called  fontanelles, 

meaning  little  fountains.     The  bones  of  the  skull  are  not 
wholly  united  till  the  child  reaches  adult  life. 


37.  The  Hyoid  Bone.  Under  the  lower  jaw  is  a  little  horse- 
shoe-shaped bone,  called  the  hyoid  bone  because  it  is  shaped 
like  a  Greek  letter  (v).  The  root  of  the  tongue  is  fastened  to 


THE   BONY  FRAMEWORK 


its  bend,  and  the  larynx  is  hung  from  it  as  from  a  hook.  To 
this  bone  are  attached  muscles  which  move  the  tongue.  The 
hyoid,  like  the  kneepan,  is  not  connected  with  any  other  bone. 

Experiment  8.  To  locate  the  hyoid  bone.  With  the  neck  resting  in 
its  natural  position,  gently  grasp  the  front  of  the  throat  with  the 
thumb  and  forefinger  just  above 
the  "Adam's  apple."  The  hyoid 
bone  can  be  plainly  felt  on  a  level 
with  the  lower  jaw  and  about  one 
inch  and  a  half  behind  it  (Fig.  1 73). 


THE  BONES  OF  THE 
TRUNK 

38.  The  Trunk  and  its  Two 
Cavities.     The  trunk  is  that 
part  of  the  body  which  sup- 
ports the  head,  and  to  which 
the   arms    and   the    legs    are 
attached.     It  has  two  impor- 
tant parts,  or  cavities. 

The  upper  part,  called  the 
thorax,  or  chest,  is  like  a  basket  or  cage  of  bone.  It  is 
formed  by  the  breastbone  in  front,  the  ribs  and  a  part 
of  the  backbone  behind.  It  contains  the  lungs  and  the 
heart. 

The  lower  part,  or  abdomen,  holds  the  stomach,  liver, 
intestines,  kidneys,  and  other  important  organs. 

The  chest  and  abdomen  are  separated  by  a  muscular 
partition  known  as  the  diaphragm,  which  serves  as  the  chief 
muscle  in  breathing. 

39.  The  Bones  of  the  Trunk.    The  principal  bones  of  the 
trunk  are  those  of  the  spine,  the  ribs,  and  the  hips. 


FIG.  17.     The  Top  of  the  Skull, 
showing  the  Sutures. 


26  OUR   BODIES   AND    HOW  WE   LIVE 

There  are  fifty-three  bones  in  the  trunk,  and  they  are 
thus  arranged. 

7  Cervical,  or  neck  vertebrae 
12  Dorsal,  or  back  vertebrae 


I.    The  Spine,  26  bones 


5  Lumbar,  or  loin  vertebrae 
i  Sacrum,  or  sacred  bone 
i  Coccyx,  or  cuckoo  bone 


II.     24  Ribs  (14  True  ribs 

(  10  False  ribs 


III.  i  Sternum,  or  breastbone 

IV.  2  Hip  bones 

40.  The  Spine.     The  spine,  or  backbone,  serves  as  a  sup- 
port for  the  whole  body.     It  is  made  up  of  a  number  of 
separate  bones  called  vertebrae,  between  which  are  placed 
elastic  pads,  or  cushions,  of  cartilage. 

These  pads  not  only  serve  to  bind  the  vertebrae  firmly 
together,  but  also  help  to  break  the  force  of  any  shock  or 
jar  which  the  spine  may  receive,  just  as  the  rubber  tires 
of  a  carriage,  an  automobile,  or  a  bicycle  lessen  the  jolting 
which  would  be  felt  without  them. 

The  spine  forms  a  pillar,  or  column  of  bones,  tapering 
towards  the  head.  The  lower  ones  are  larger  and  stronger 
to  enable  them  to  bear  the  weight  of  those  above  them. 

At  the  top  are  seven  cervical,  or  neck  vertebrae ;  below 
them  are  the  twelve  dorsal,  or  back  vertebrae,  from  which 
spring  the  ribs. 

The  next  five  bones,  called  the  lumbar,  or  loin  vertebrae, 
are  thicker  and  larger. 

41.  The  Sacrum  and  Coccyx.     The  twenty-four  vertebrae 
rest   on  and  above  a  strong,   three-sided  bone  called  the 
sacrum,  or  sacred  bone,  which  is  wedged  in  between  the  hip 
bones  like  the  keystone  of  an  arch.     This  bone  supports 
the  spine  and  breaks  the  force  of  sudden  shocks. 


THE   BONY   FRAMEWORK 


Joined  to  the  lower  end  of  the  sacrum  is  a  little,  tapering 
bone,  made  up  of  several  little  bones, 
called  the  coccyx.     It  is  so  named  from 
its  fancied  resemblance  to  the  beak  of 
a  cuckoo. 

42.  How  the  Bones  of  the  Spine  are 
arranged.      Each  bone,  or  vertebra,  of 
the  backbone  has  a  hole  within  it,  and 
the  separate  bones  are  so  placed,  one 
above  the  other,  that  these  holes  form 
a  continuous  tube  or  canal,  down  which 
passes  the  spinal  cord.    Imagine  a  num- 
ber of  spools  placed   one   on  another. 
The  central  hole  through  each  would  be 
exactly  over  the  other,  and  there  would 
be  one  .long  tube  or  channel  through 
the  whole   string  of    spools.      In    this 
bony    canal    the    spinal   cord    lies    pro- 
tected from  injury. 

From  each  vertebra  projects  a  spine 
or  thorn  of   bone,  to  which  are  fas 
tened  muscles  which  keep  the  flexible 
backbone  erect  and  lift  the  head  and 
shoulders.     The  row  of  spines  along 
the  whole  length  of  the  backbone 
forms  a  ridge,  which  can  be  easily 
felt  by  pressing  with  the  fingers  up 
and  down  the  middle  of  the  back. 

43.  The  Wonders  of   the   Spine. 
The  spine  is  built  in  a  most  curious 
and  wonderful  manner,  —  firm,  and 
yet  elastic;  so  stiff  that  it  will  bear 


COCCYX 


FIG.  1 8.     The  Spinal 
Column. 


28 


OUR   BODIES   AND   HOW  WE   LIVE 


a  heavy  weight  and  yet  bend  like  rubber.  It  is  a  tapering 
pile  of  odd-shaped  bones,  so  admirably  planned  and  so 
wonderfully  put  together,  that  the  delicate  brain  resting 
upon  it,  and  the  spinal  cord  hidden  within  its  bony  canal, 
are  not  often  hurt. 

The  most  daring  acrobat  rarely  breaks  the  bones  of  his 
spine  or  puts  them  out  of  place.  It  is  not  an  uncommon 
thing  to  see  show  people  bend  their  backs  until  they  can 

put  their  heads  on  the 
ground,  or  clasp  their 
legs  around  their  necks. 

Experiment  9.  To  illus- 
trate the  movement  of  torsion 
in  the  spine.  Sit  upright  with 
the  back  and  shoulders  well 
applied  against  the  back  of  a 
chair.  Note*  that  the  head 
and  neck  can  be  turned  as 
much  as  60°  or  70°.  Now 
bend  forward  so  as  to  let  the 
lumbar  vertebrae  come  into 
play,  and  the  head  can  be 
turned  30°  farther. 

44.  The  Ribs.  The 
ribs  are  long,  flat,  and 
curved  bones  which  bend 
round  the  chest  somewhat  like  the  hoops  of  a  barrel.  There 
are  twenty-four  ribs,  —  twelve  on  each  side. 

The  ribs  are  joined  to  the  backbone  behind,  and  most  of 
them  are  joined  in  front,  directly  or  indirectly,  to  a  flat, 
narrow  bone,  which  is  shaped  somewhat  like  an  ancient 
sword  or  dagger.  It  forms  the  middle  front  wall  of  the 
chest  and  is  called  the  sternum,  or  breastbone, 


FIG.  19.     Thorax. 
Anterior  view. 


THE   BONY   FRAMEWORK  29 

Counting  from  the  neck,  the  first  seven  pairs  are  called 
the  true  ribs.  They  are  all  joined  directly  to  the  breastbone. 

The  five  lower  pairs,  known  as  the  false  ribs,  are  not  joined 
to  the  breastbone  at  all.  Cartilages  connect  the  first  three 
of  them  with  each  other,  and  with  the  last  of  the  true  ribs. 

The  lowest  two  pairs  of  ribs  are  often  known  as  the  float- 
ing ribs,  because  they  are  not  even  joined  by  cartilages,  but 
are  quite  free  in  front. 

45.  The  Hips  and  the  Pelvis.     The  lower  part  of  the 
trunk  is  formed  by  two  large,  irregular  bones,  very  firm 
and  strong,   called  the  hip,  or  haunch  bones.     They  are 
joined  to  the  sacrum  behind,  and  to  each  other  in  front. 

The  two  hip  bones,  with  the  sacrum  and  coccyx,  form  a 
kind  of  bony  basin  called  the  pelvis,  which  contains  and 
protects  several  important  organs. 

Each  hip  bone  has  a  cup-shaped  cavity  on  its  side,  into 
which  the  rounded  head  of  the  thigh  bone  fits.  It  is  called 
the  acetabulum,  meaning  vinegar  cup,  because  it  has  the 
shape  of  the  vinegar  caps  used  by  the  Romans. 

THE   BONES    OF   THE   UPPER   LIMBS 

46.  The  Bones  of  the  Upper  Limbs.     Each  of  the  upper 
limbs  consists  of  the  shoulder,  arm,  forearm,  and  hand. 

The  thirty-two  bones  of  each  upper  limb  are  usually 

classified  as  follows. 

f  Scapula,  or  shoulder  blade 
Shoulder  |  clavicle>  or  collar  bone 

Arm  Humerus,  or  arm  bone 

{  Ulna 
Forearm  |  Radius 

8  Carpal,  or  wrist  bones 
Hand        \     5  Metacarpal  bones 

14  Phalanges,  or  finger  bones 


30  OUR   BODIES   AND   HOW  WE   LIVE 

47.  The  Bones  of  the  Shoulder  and  Arm.     There  are  two 
bones  in  the  shoulder,  and  they  serve  to  fasten  the  arm  to 
the  trunk.     These  are  the  scapula,  or  shoulder  blade,  and 
the  clavicle,  or  collar  bone. 

The  shoulder  blade  is  a  large,  flat,  three-sided  bone,  which 
is  placed  on  the  upper  and  back  part  of  the  chest.  On  the 
outer  side  it  has  a  saucerlike  cavity  on  which  the  rounded 

head  of  the  arm  bone  rests. 

The  collar  bone  is  a  long,  nar- 
row bone,  with  a  double  curve 
like  the  italic  letter/.  It  serves, 
like  the  keystone  of  an  arch,  to 
keep  the  shoulders  wide  apart, 
and  thus  to  allow  the  arms  great 
freedom  of  movement .  Its  inner 
end  is  tied  to  the  breastbone, 
and  its  outer  to  the  shoulder 
blade. 

The  humerus,  a  long,  hollow 
bone,  rests  against  a  shallow 

The  Scapula.  ^^    ^    ^    shoulder    bhde 

It  is  joined  at  the  elbow  to  the  bones  of  the  forearm. 

48.  The  Bones  of  the  Forearm.     The  forearm  contains 
two  long,  hollow  bones,  the  ulna  and  the  radius. 

The  ulna,  or  elbow  bone,  is  the  larger  of  these  two  bones. 
It  is  joined  to  the  humerus  by  a  hinge  joint  at  the  elbow. 
It  is  on  the  same  side  as  the  little  finger. 

The  radius,  queerly  named  because  it  is  supposed  to 
resemble  one  of  the  spokes  of  a  wheel,  is  the  long,  slightly 
curved,  outer  bone  of  the  forearm.  It  is  on  the  same  side 
as  the  thumb.  Its  upper  end  is  fastened  both  to  the  ulna 
and  the  humerus. 


THE   BONY   FRAMEWORK 


The  radius  is  fastened  to  the  ulna  in  such  a 
manner  that  it  can  glide  partly  round  it.  This 
gives  us  the  power  of  twisting  the  hand. 

Experiment  10.  To  illustrate  the  action  of  the  radius. 
Rest  the  forearm  on  a  table,  with  the  palm  up.  The 
radius  is  on  the  outer  side  (thumb)  and  parallel  with 
the  ulna.  If  now,  without  moving  the  elbow,  we  turn 
the  hand  as  if  to  pick  up  something  from  the  table,  the 
radius  may  be  seen  and  felt  crossing  over  the  ulna, 
while  the  latter  bone  has  not  moved. 


FIG.  21.  The 
Humerus. 


49.  The  Hand.  The  hand  consists  of  the 
eight  bones  of  the  wrist  (carpal),  the  five 
long  bones  of  the  palm  (metacarpal),  and  the 
fourteen  small  bones  of  the  fingers 
(phalanges).  Each  finger  has 
three  bones,  each  thumb  two.  The 
bones  of  the  fingers  are  arranged 
in  three  rows,  as  shown  by  closing 
the  hand. 

The  twenty-seven  bones  of  the 
hand  are  held  in  place  by  strong  but  flexible 
ligaments.  By  this  beautiful  contrivance,  the 
greatest  strength  and  mobility  are  given  to 
the  hand,  which  is  thus  fitted  for  all  kinds  of 
work,  from  grasping  heavy  hammers  to  han- 
dling the  pen,  playing  difficult  music  on  the 
piano,  and  threading  the  finest  needle. 

THE  BONES   OF  THE  LOWER  LIMBS 
50.    The  Lower  Limbs.     The  general  struc- 


ture and  number  of  the  bones  of  the  lower  limbs 


FIG.  22.    The 
Ulna  and  the 

bear  a  striking  similarity  to  those  of  the  upper      Radius. 


OUR   BODIES   AND   HOW   WE   LIVE 


limbs.  The  two  sets  of  limbs,  although  differing  in  many 
points,  are  built  on  the  same  general  plan,  the  one 
being  adapted  for  grasping  and  the  other  for  walking. 


FIG.  23.    Bones  of  the  Hand  and  Wrist,  as  shown  by  an  X-Ray  Photograph. 
Two  rings  are  plainly  shown. 

51.  The  Bones  of  the  Lower  Limbs.  The  lower  limb,  like 
the  arm,  is  arranged  in  three  parts,  —  the  thigh,  leg,  and  foot. 

The  thirty  bones  of  each  lower  limb  are  usually  classified 
as  follows. 


Thigh  Femur,  or  thigh  bone 
f  Tibia,  or  shin  bone 

Leg  -J  Fibula,  or  splint  bone 
[  Patella,  or  kneecap 


f    7  Tarsal,  or  ankle  bones 
Foot «    5  Metatarsal,  or  instep  bones 
[  14  Phalanges,  or  toe  bones 


THE   BONY   FRAMEWORK 


33 


i 


52.  The  Thigh  Bone.     The  femur,  or  thigh 
bone,  the  largest   and  heaviest   bone   in  the 
body,  reaches  from  the  hip  to  the  knee.     It 
has  a  rounded  head,  which  fits  into  the  cup- 
like  cavity  in  the  hip  bone  which  has  already 
been  mentioned. 

53.  The  Bones  of  the  Leg.    The  leg  consists, 
like  the  forearm,  of  two  bones.     The  larger, 
a  strong,  three-sided  bone  with  a  sharp  edge 
in  front,  is  called  the  tibia.     It  is  commonly 
known  as  the  shin  bone. 

The  smaller  bone,  bound  at 
both  ends  to  the  tibia,  as  a  pin 
is  to  a  brooch,  is  called  the  fibula, 
meaning  a  buckle  or  clasp.  It  is 
a  long,  slender  bone  on  the  out- 
side of  the  leg,  and  its  lower  end 
forms  the  outer  ankle 

Covering  the  knee  joint  in  part 
is  a  flat,  three-sided  bone,  called 
the  patella,  or  kneepan,  which 

FIG.  24.     The 

Femur.        helps  to  protect  the  front  of  the 

knee  joint. 

54.  The  Bones  of  the  Foot.  The  foot  con- 
sists of  twenty-six  bones,  which  are  known 
as  the  tarsal  and  metatarsal  bones,  and  the 
phalanges. 

The  seven  tarsal,  or  ankle  bones  form  the 
heel,  the  ankle,  and  part  of  the  sole  of  the 

foot.     These  bones  are   tied  firmly  together 

,.  .      FIG.  25.     The 

by  straps,  or  ligaments,  and  are  strong  enough     Tibia  and  the 

to  bear  the  weight  of  the  body.  Fibula. 


34  OUR   BODIES   AND    HOW  WE   LIVE 

The  large  bone,  which  projects  backwards,  is  the  heel  bone. 
It  is  connected  with  the  great  calf  muscles  of  the  leg  by  a 
very  strong  cord,  or  tendon,  called  the  tendon  of  Achilles.1 

The  five  metatarsal,  or  instep  bones  correspond  to  the 
palm  bones  of  the  hand. 

The  phalanges  are  the  fourteen  bones  of  the  toes. 

55.  Why  the  Foot  is  built  in  the  Form  of  an  Arch.  The 
foot  is  built  in  the  form  of  a  half  dome  or  half  arch.  This 
is  to  afford  a  broad,  strong  surface  for  the  support  of  the 
weight  of  the  body.  The  bones  of  the  toes  and  the  heel 


FIG.  26.     The  Bones  of  the  Foot. 

form  the  piers,  while  the  little  bones  wedged  in  between 
the  metatarsal  bones  and  the  heel  make  up  the  keystone  of 
the  arch.  This  arch  gives  a  certain  amount  of  spring  and 
elasticity  to  the  feet,  and  hence  it  is  of  the  utmost  impor- 
tance in  preventing  jars  and  jolts. 

Experiment  11.  Place  your  bare  foot  in  water  and  then  stand  on 
a  dry  board.  The  imprint  on  the  board  will  show  you  how  much  of 
the  foot  touches  the  ground,  and  thus  the  extent  of  the  arch. 

56.  How  Bones  are  joined  together.  The  place  where 
two  bones  join  together  is  called  a  joint  or  an  articulation. 

Joints  vary  according  to  the  kind  and  amount  of  motion. 
In  all  joints  the  essential  parts  are  the  same. 

1  The  warlike  deeds  of  this  famous  Greek  hero  were  sung  by  Homer. 
According  to  the  story,  Achilles  received  his  death  wound  in  the  heel,  no 
other  part  of  his  body  being  vulnerable. 


THE   BONY  FRAMEWORK 


35 


The  joint  end  of  the  bones  is  smooth,  moist,  and  tipped 
with  a  thin  layer  of  cartilage,  called  hyaline  cartilage. 
This  smooth  and  glistening  covering  is  bathed  with  a 
sticky  fluid  called  the  synovial  fluid,  so  named  because  it  is 
like  the  white  of  a  raw  egg.  This  is  the  liquid  often 
spoken  of  as  "joint  oil,"  furnished  by 
nature  to  allow  the  rubbing  surfaces 
to  move  smoothly  over  one  another, 
and  thus  prevent  too  much  wear  and 
tear. 

57.  Different  Kinds  of  Joints.  There 
are  two  principal  kinds  of  joints,  the 
imperfect,  or  practically  immovable,  and 
the  perfect,  or  movable.  Thus,  the  bones 
of  the  head,  as  we  have  seen,  are  firmly 
dovetailed  by  jagged  edges,  which 
grow  into  each  other  from  infancy. 
These  are  known  as  imperfect  joints. 

Movable   joints    allow  the  bones   to 
glide  on  each  other  with  more  or  less 
freedom  of  motion, 
cording  to  the  motion  needed. 

Thus,  the  joint  at  the  hip  is  called 
a  ball-and-socket  joint,  and  is  not  unlike 
a  child's  toy  cup  and  ball,  because 
the  rounded  head  of  the  thigh  bone  fits  into  a  socket  in 
the  hip  bone.  The  rounded  head  of  the  arm  bone,  as  we 
have  learned,  works  in  the  shallow,  saucerlike  cavity  of 
the  shoulder  blade.  Such  a  joint  allows  a  great  variety 
of  motion  in  almost  every  direction. 

Bones  at  certain  joints  are  grooved  and  ridged  so  that 
one  bone  can  glide  over  the  other  to  and  fro,  like  the  lid  of 


They  differ  ac-    Fia  27'    Showins  how 

the  Ends  of  the  Bones 
are  shaped  to  form 
the  Elbow  Joint. 

The  cut  ends  of  a  few 
ligaments  are  seen. 


36  OUR   BODIES  AND    HOW   WE    LIVE 

a  box  or  a  door  on  its  hinges.  This  is  called  a  hinge  joint.  The 
elbow  joint  is  a  good  example  of  this  forward  and  backward 
movement  ;  we  can  only  bend  and  extend  it. 

Other  hinge  joints  are  found  at  the  knee,  and  between 
the  lower  jaw  and  the  cranium.     The  last  permits  some 
motion  from  side  to  side,  and  is  therefore 
called  an  imperfect  hinge  joint. 

Experiment  12.  Sit  in  a  chair  and  extend 
the  right  leg.  Place  the  right  heel  on  the  floor 
and  turn  the  foot  from  side  to  side.  The  thigh 
bone  can  be  felt  rotating  in  the  upper  part  of 
the  thigh.  Note  that  while  the  thigh  bone 
moves  through  a  small  space,  that  described  by 
the  tips  of  the  toes  is  much  larger. 

58.  How  Bones  are  fastened  to  Each 
Other.  The  bones  are  fastened  together, 
kept  in  place,  and  their  movements 
limited,  by  tough  and  strong  bands,  or 
straps,  called  ligaments,  from  a  word 
meaning  to  bind.  They  may  be  seen  in 
the  movable  joints,  —  of  the  calf,  sheep, 
or  chicken,  —  and  have  the  look  of  white, 
silvery  cords  or  bands. 
A  Powerful  Some  of  the  ligaments  are  as  thin  as 

at  the       thin  tissue  paper  ;  while  otherS)  as 


at  the  side  of  the  knee,  or  at  the  shoulder, 
are  much  thicker.  Some  cross  each  other,  as  in  the  knee- 
joint  ;  while  others  go  all  round  the  joint,  and  completely 
shut  it  up  in  a  bag.  This  prevents  the  bones  from  being 
easily  dislocated,  or  slipped  out  of  place. 

It  is  sometimes  a  difficult  matter  to  carve  a  fowl,  because 
one  has  to  cut  through  the  ligaments  before  he  can  cut  the 


THE    BONY   FRAMEWORK  37 

limbs  apart  to  serve  it  in  pieces.  There  may  be  the  same 
difficulty  in  separating  the  bones  in  a  shoulder  or  leg  of 
mutton,  because  they  are  held  firmly  together  by  ligaments. 

59.  Use  of  the  Bones.  Bones  serve  many  useful  pur- 
poses. They  preserve  the  general  shape  of  the  body.  The 
skeleton,  as  we  have  seen,  is  its  framework,  which  gives 
protection,  leverage,  and  support  to  the  soft  and  fleshy 
parts  of  our  bodies. 

Bones  protect  the  soft  organs  of  the  body.  The  bones 
of  the  head  protect  the  soft  and  delicate  brain.  The 
ribs  inclose  the  heart  and  lungs  in  a  large  cage  of  bone. 


FIG.  29.     Ligaments  of  the  Foot  and  the  Ankle. 

Passageways  and  little  cavities  are  hollowed  out  of  solid 
bone  to  lodge  and  shield  important  organs.  There  are 
grooves  and  canals  in  the  bones  which  serve  to  receive 
and  protect  tender  organs,  delicate  nerves,  and  tiny  blood 
vessels. 

The  surfaces  of  many  bones  are  fitted  with  grooves,  knobs, 
and  sharp  edges  to  which  muscles  are  fastened.  This 
arrangement  of  the  muscles  helps  us  to  stand  erect  and 
make  the  countless  movements  of  the  body  with  ease  and 
quickness. 


OUR  BODIES   AND    HOW   WE    LIVE 


FIG.  30.     A  Broken  Radius. 


60.  Repair  of  Broken  Bones.  When  a  bone  is  broken, 
blood  trickles  out  between  the  injured  parts,  and  after- 
wards gives  place  to  a  sticky,  watery  fluid,  which  gradually 
becomes  thicker,  like  sirup  or  jelly.  This  is 
slowly  replaced  by  a  new  bone  structure,  and 
forms  a  kind  of  cement  to  hold  together  the 

broken  ends. 

Nature  does  not 
spare  her  healing 
cement.  The  ex- 
cess bulges  out 
around  the  place 
of  union,  over  which  a  bunch  may  be  felt  under  the  skin 
for  years.  In  young  people,  a  broken  bone  will  knit  together 
in  two  or  three  weeks  ;  while  in  grown-up  people  six  weeks  or 
more  will  be  required.  In 
aged  persons,  a  broken 
bone  may  prove  a  tedious 
and  often  a  serious  matter. 
When  a  bone  is  broken, 
the  ends  tend  to  "ride" 
over  each  other,  because  the 
muscles  tend  to  pull  the 
broken  portions  apart; 
hence  the  need  of  a  surgeon 
to  "  set"  the  bone  by  draw- 
ing the  injured  parts  into  place,  and  keeping  them  in 
position  by  splints  and  bandages  properly  applied. 

After  a  bone  has  been  once  broken,  it  is  fragile  for  some 
time,  and  great  care  should  be  taken,  especially  with  chil- 
dren, for  fear  that  it  may  be  broken  a  second  time  before 
it  has  properly  healed  (Sec.  405,  Figs.  179  and  185). 


FIG.  31.     A  Broken  Clavicle. 


THE   BONY  FRAMEWORK 


39 


61.  Hints  about  the  Health  of  Bones.  The  bones  of 
children  are  flexible  and  capable  of  being  bent  by  long- 
continued  strain,  because  they  contain  more  animal  matter 
than  in  later  years.  Therefore  great 
care  must  be  taken  with  the  positions 
which  children  take  at  home,  at  school, 
and  elsewhere. 

Young  people  should  not  get  into 
the  habit  of  taking  hurtful  positions, 
such  as  sliding  down  into  the  seat, 
sitting  on  the  foot  or  on  the  small  of 
the  back.  Bending  over  too  much 
while  reading,  writing,  sewing,  prac- 
ticing on  the  piano,  or  doing  other 
work,  may  cause  spinal  curvature  and 
round  shoulders.1 

The  use  of  tight  and  high-heeled 
boots  and  shoes  cannot  be  too  strongly 
condemned  as  both  hurtful  and  ugly. 
High  heels  throw  the  weight  of  the 
body  forward,  and  force  the  foot  down 
onto  the  toes.  This  will  in  time  not  only  crowd  the  toes 
out  of  proper  shape,  causing  tender  feet,  corns,  bunions, 

1  Children  who  go  to  school  at  six  or  seven  years  of  age  are  often  com- 
pelled to  sit  on  a  badly  shaped  chair,  sometimes  with  no  support  for  the 
back.  The  muscles  become  tired  and  the  child  leans  to  one  side,  usually 
to  the  right. 

A  narrow  space  between  the  seat  and  the  desk  obliges  the  child  to  push 
between  them,  so  that,  in  girls  particularly,  a  drag  is  exerted  on  one 
shoulder;  or  the  skirts  form  an  uneven  cushion,  tilting  the  spinal  column 
out  of  the  perpendicular.  Even  in  grown  men  and  women,  occupations 
requiring  a  one-sided  muscular  action  affect  the  vertebrae,  and  therefore  the 
shape  of  the  spine.  In  children  the  much  softer  bones  are  still  more  readily 
affected. 


FIG.  32.     A  Broken 
Tibia. 


OUR  BODIES  AND   HOW  WE   LIVE 


distorted  joints,  and  ingrowing  nails,  but,  in  many  instances, 

tends  to  make  the  gait  stiff  and  ungainly.1 

62.   Effect  of  Alcohol  upon  the  Cell  Growth  of  the  Bones. 

The  bones  grow  mainly  during  the  earlier  years  of  life,  and 

yet  they  do  not  reach  their  full  growth  until  about  the 
^^^^^•••^fc^  twenty-fifth    year.       It    is 

said  that  the  skull  grows 
even  after  that  age.  Now, 
we  know  that  a  person's 
form  depends  to  a  great 
extent  upon  the  size  and 
shape  of  his  bones,  because, 
as  we  have  seen,  they  make 
up  the  framework  of  the 
body.  It  is  plainly  evident, 
then,  that  the  bone  cells, 
which  are  busily  building 
up  the  bony  tissues  while 
we  are  young,  must  not  be 
injured  or  badly  nourished, 
otherwise  our  bones  may 
become  feeble  and  stunted 
in  their  growth. 


FIG.  33.  Showing  how  the  Bones  of 
the  Skull  may  be  artificially  de- 
formed by  "  Head  Binding." 

From  the  photograph  of  a  "triangular" 
skull  found  in  an  Indian  grave  in  Ancon, 
Peru. 


1  Most  deformities  of  the  feet  are  developed  during  childhood,  while  the 
bones  are  soft,  the  ligaments  less  resistant,  and  the  muscles,  together  with 
the  other  foot  structures,  are  undergoing  rapid  changes  in  development. 

The  power  of  the  foot  as  a  sustainer  of  the  weight  of  the  body  is 
readily  understood.  The  heel,  great  toe,  and  outer  side  of  the  foot  form 
the  three  points  of  a  tripod.  An  outward-crowded  great  toe  decreases 
the  utility  of  the  foot  to  just  such  a  degree  as  it  is  forced  from  its  normal 
position. 

Toeing  in  is  often  due  to  the  unconscious  effort  to  lessen  the  strain  on  the 
arch  of  the  foot,  produced  by  badly  formed  shoes.  Few  children  will  toe 
in  if  they  wear  properly  shaped  shoes. 


THE   BONY   FRAMEWORK  41 

Alcoholic  liquors  tend  to  retard  the  growth  of  the  cells, 
bone  cells  included,  and  prevent  their  proper  development. 
Hence  alcohol  in  all  its  forms  is  especially  injurious  to 
young  people,  as  it  checks  the  cell  growth  of  the  bones 
and  thus  hinders  the  building  up  of  the  bony  framework.1 

63.  Effect  of  Tobacco  upon  the  Bony  Cell  Growth.  What 
we  have  just  read  of  the  effect  of  alcoholic  liquors  in  retard- 
ing the  cell  growth  of  the  bones  and  thus  stunting  the 
bony  framework  holds  good  of  tobacco.  This  powerful 
narcotic  is  peculiarly  injurious  to  the  young,  as  the  bony 
cell  growth  is  easily  disturbed  at  this  time  by  noxious  sub- 
stances. If  the  bones  are  defrauded  of  their  proper  build- 
ing material  because  the  blood  sent  to  nourish  their  cells 
is  poor  in  quality  or  loaded  with  narcotics,  they  become 
undersized  or  weakened. 

A  well-developed  framework  is  something  to  be  prized. 
No  thoughtful  boy  or  girl  will  risk  losing  it  by  indulging  in 
the  use  of  tobacco  or  any  other  narcotic.2 

1  The  injurious  effect  of  alcohol  on  the  entire  development  of  the  child 
is  evident  from   the  fact  that  children  who  drink  spirituous  liquors  are 
noticeably  stunted  in  growth.  —  ADOLF  FRICK,  M.D. 

The  use  of  alcoholic  drinks  exerts  an  injurious  influence  upon  the  mental 
and  physical  development  of  children.  —  DR.  FIEDLER,  Superintendent  of 
the  Dresden  City  Hospital,  Germany. 

2  Smoking  prevents  a  healthy  nutrition  of  the  several  structures  of  the 
body.     Hence  comes,  especially  in  young  persons,  an  arrest  of  the  growth 
of  the  body,  low  stature,  an  unhealthy  supply  of  blood,  and  weak  bodily 
powers.  —  DR.  J.  COPLAND,  F.R.S.,  of  England. 

Stunted  growth,  impaired  digestion,  palpitation,  and  other  evidences 
of  nerve  exhaustion  and  irritability  have  again  and  again  impressed  a  les- 
son of  abstinence  from  tobacco  which  has  hitherto  been  far  too  little 
regarded.  —  London  Lancet. 


REVIEW   ANALYSIS 


THE  BONES  OF  THE  BODY 


' 

i  Frontal 

2  Parietal 

I.  CRANIUM    \ 

2  Temporal 

(8  bones)      ] 

i  Occipital 

i  Sphenoid 

i  Ethmoid 

f    2  Malar 

2  Nasal 

THE   HEAD 
(29  bones) 

II.  FACE           ) 

2  Superior  maxillary 
i  Lower  maxillary 

(14  bones)    ) 

2  Palate 

2  Lachrymal 

i  Vomer 

2  Turbinated 

' 

III.  THE  EAR    ) 

Hammer 

(6  bones)      ( 

Anvil 
Stirrup 

IV.  HYOID  BONE 

i7  Cervical  vertebrae 

I.  SPINAL  COLUMN  ) 

12  Dorsal  vertebras 

(26  bones)             } 

5  Lumbar  vertebrae 
Sacrum 

THE   TRUNK 

Coccyx 

(53  bones) 

II.  THE  RIBS  ) 

(24  bones)      ) 

:i4  True  ribs 
10  False  ribs 

III.  STERNUM 

,  IV.  Two  HIP  BONES 

I.  SHOULDER   . 

Scapula 

•1 

Clavicle 

II.  ARM    

Humerus 

UPPER  LIMBS 
(64  bones) 

III.  FOREARM     .     .     .     .  x 

f        Ulna 
Radius 

IV.  HAND  , 

'    8  Carpal 
5  Metacarpal 

, 

14  Phalanges 

I.  THIGH     

Femur 

Tibia 

II    LEG 

T?ihiila 

LOWER   LIMBS 
(60  bones) 

.T  IDUia 

L        Patella 
"    7  Tarsal 

III.  FOOT  

5  Metatarsal 

^  14  Phalanges 

THE    BONY   FRAMEWORK  43 


QUESTIONS  ON  THE  TEXT 

I.  What  is  meant  by  the  skeleton,  and  what  are  its  uses?     2.  Of 
what  is  bone  composed  ?     3.  What  experiments  illustrate  the  compo- 
sition of  bone  ?     4.  Explain  the  general  structure  of  bone.     5.  What 
can  you  tell  of  the  general  shape  of  bones?     6.  How  does  bone  look 
under  the  microscope  ?     7.  Name  the  principal  divisions  of  the  human 
skeleton.     8.  Into  what  parts  is  the  head  divided?     9.   Mention  the 
bones  of  the  cranium.     10.  Describe  each  bone  of  the  cranium. 

II.  Give  the  names  of  the  bones  of  the  face.     12.  Describe  the 
larger  bones  of  the  face.     13.  Describe  the  smaller  bones  of  the  face. 
14.  How  are  the  bones  of  the  head  joined  together?     15.  Where  is 
the  hyoid  bone  ?    16.  Of  what  parts  does  the  trunk  consist  ?    17.  Men- 
tion the  bones  of  the  trunk.    18.  Describe  the  spine  in  full.     19.  How 
are  the  bones  of  the  spine  arranged  ?     20.  Describe  in  some  detail 
the  ribs. 

21.  How  are  the  bones  of  the  pelvis  arranged?  22.  Name  the 
bones  of  the  upper  limbs.  23.  Describe  the  bones  of  the  shoulder 
and  arm.  24.  Describe  the  bones  of  the  forearm.  25.  Tell  what  you 
know  about  the  bones  of  the  hand.  26.  Name  the  bones  of  each 
part  of  the  lower  limbs.  27.  Describe  the  bones  of  the  thigh  and 
leg.  28.  Tell  what  you  know  about  the  bones  of  the  foot.  29.  How 
are  bones  joined  together  ?  30.  Describe  the  different  kinds  of  joints 
and  illustrate. 

31.  Describe  ligaments  and  explain  their  uses.  32.  Explain  the 
general  uses  of  bones.  33.  What  happens  when  bones  are  broken? 
34.  Give  some  hints  about  the  health  of  bones.  35.  What  is  the 
effect  in  general  of  alcohol  upon  the  growth  of  bones?  36.  How 
does  tobacco  injure  the  growth  of  bones  ?  37.  Give  orally,  in  order 
of  Review  Analysis,  p.  42,  the  bones  of  the  head.  38.  Give  orally 
in  order  the  bones  of  the  trunk.  39.  Mention  the  bones  of  the  upper 
limbs.  40.  Give  orally  the  bones  of  the  lower  limbs.  41.  Write  on  the 
blackboard,  in  tabular  form,  the  names  of  all  the  bones  of  the  body, 
as  arranged  in  Review  Analysis,  p.  42. 


CHAPTER    III 
THE  MUSCLES  AND  HOW  TO  USE  THEM 

64.  Muscles  as  the  Organs  of  Motion.     The  energy  set 
free  in  the  burning,  or  oxidation,  which  is  constantly  going 
on  in  the  bodily  tissues  is  the  source  of  the  active  powers 
of  our  bodies. 

These  active  powers  are  mainly  manifested  in  the  form 
of  motion  or  movement,  either  of  a  part  of  the  body  or  of 
the  body  as  a  whole. 

These  total  or  partial  bodily  movements  are  produced  by 
muscles,  —  the  organs  of  motion. 

65.  Variety  of  Muscular  Action.     The  lean  meat  or  flesh 
which  forms  the  rounded,  shapely  covering  for  our  bony 
framework  is  muscle.     When  we  eat  beefsteak  or  mutton 
we  are  eating  muscle.     Muscles,  of  which  there  are  more 
than   four  hundred  in   the  body,  are  also  the  means  by 
which  the  body  is  kept  in  the  erect  position  and  in  other 
positions  which  call  for  effort. 

The  limbs  are  moved  by  muscles.  Even  the  motions  of 
the  stomach  and  the  action  of  the  heart  are  caused  by 
muscles.  Muscles  move  the  skin.  In  many  animals  this 
action  is  well  marked,  as  when  the  horse  shakes  his  hide 
to  get  rid  of  biting  flies.  Muscles  move  the  bones,  the 
lips,  and  the  eye. 

In  brief,  all  motion  in  our  bodies  is  dependent  upon  muscular 
activity. 

44 


THE   MUSCLES   AND   HOW  TO   USE   THEM 


45 


66.  Two  Great  Kinds  of  Muscles.  We  shall  learn  later 
that  all  the  varied  movements  of  the  muscles  are  carried 
on  under  the  control  of  the  nervous 
system.  Some  of  these  movements  are 
under  the  control  of  our  will,  while 
others  are  managed  by  the  nervous 
system  quite  independently  of  the  will. 
For  instance,  we  know  we  have  it  in 
our  power  to  decide  when  to  move  our 
head,  our  hands,  or  our  feet.  The  mus- 
cles whose  duty  it  is  to  move  them  are 
under  the  control  of  our  will.  We  call 
these  voluntary  muscles. 

On  the  other  hand,  our  will  has  no 
control  over  the  muscles  of  the  stomach, 
the  heart,  or  any  of 
the  internal  organs. 
The  work  of  these 
organs  goes  on  night 
and  day  without  regard  to  our  will.  We 
call  these  involuntary  muscles. 

Experiment  13.  To  show  the  general  appear- 
ance of  the  muscles.  Obtain  the  lower  part  of  a 
sheep's  leg,  with  most  of  the  lean  meat  and  the  FIG.  35.  A  Portion  of 
hoof  left  on.  One  or  more  of  the  muscles,  with  Striped  Muscular 
their  bundles  of  fibers,  fasciae,  and  tendons,  are 
readily  made  out  with  a  little  careful  dissection. 


FIG.  34.     A  Portion 
of  a  Striped  Mus- 
cular Fiber. 
Highly  magnified. 

A,  fiber  separating  into 
disks;  B,  fibrilke; 
C,  cross-section  of  a 
disk. 


Fiber,     showing 
Stripes  and  Nuclei. 
Highly  magnified. 


Experiment  14.  To  show  the  gross  structure 
of  muscle.  Take  a  small  portion  of  a  large  muscle,  as  a  strip  of 
lean  corned  beef.  Pick  the  bundles  and  fibers  apart  with  fine  needles 
until  they  are  so  fine  as  to  be  almost  invisible  to  the  naked  eye.  Con- 
tinue the  experiment  with  the  help  of  a  hand  magnifying  glass  or  a 
microscope. 


OUR   BODIES   AND    HOW  WE   LIVE 


67.  The  General  Build  of  Voluntary  Muscles.     The  vol- 
untary muscles,  although  they  seem  to  be  solid  masses  of 
red  meat,  really  consist  of  separate  bundles  of  flesh  held 
together  by   a  very  thin  web   of    connective  tissue,   not 
unlike  the  thinnest  of  tissue  paper.     Each  bundle  of  flesh 
is  a  muscle  with  its  own  set  of  blood  vessels  and  nerves, 
and  is  inclosed  in  its  own  sheath  of  connective  tissue. 

68.  How  the  Voluntary  Muscles  look  under  the  Micro- 
scope.    If  the  tiniest  bit  of  a  voluntary  muscle  be  examined 
with  the  microscope,  it  is  found  to  consist  of  bundles  (fas- 
ciculi) of  separate  fibers  arranged  side  by  side.     Each  sepa- 
rate fiber  is  inclosed 
in   an    elastic    sheath 
(sarcolemma) . 

These  tiny  fibers 
are  seen  to  be  marked 
crosswise  with  dark 
stripes,  and  to  be  sepa- 
rated at  each  stripe 
into  disks. 

On  account  of  the 
cross  markings  on  the 
fibers  these  muscles 
are  often  called  striped 
or  striated  muscles 

}6.     Blood  Vessels  in  a  Piece  of  Striped   /Figs.    34    and    35). 

69.  The  Involun- 
tary Muscles.  The 
involuntary  muscles  consist  of  ribbon-shaped  bands  which 
surround  hollow  tubes  or  cavities  in  the  body.  They  are 
never  attached  to  bony  levers  nor  are  they  furnished  with 
tendons,  as  are  the  voluntary  muscles. 


FIG. 


Muscle  as  seen  under  the  Microscope. 
Magnified  340  times. 


THE    MUSCLES   AND    HOW  TO    USE   THEM         47 

Under  the  microscope  these  muscles  are  found  to  con- 
sist, not  of  fibers,  but  of  long,  spindle-shaped  cells,  bound 
together  in  such  a  way  as  to  form  bands  or  ribbons.  They 
are  often  called  unstriated  or  unstriped 
muscles. 

70.  How  Muscles  contract.      Muscles 
have   a   peculiar    power   of    their    own. 
This  is  the  power  to  contract  throughout 
their  length  or  to  become  shorter  and 
thicker. 

Contraction  is  not,  however,  the  nat- 
ural state  of  a  muscle.  After  a  longer 
or  shorter  time  it  is  tired  and  begins 
to  relax.  Even  the  heart,  the  hardest 
working  muscle  of  the  body,  rests  be- 
tween its  beats. 

In  order  to  contract,  a  muscle  must  FlG-  37-  A  Spindle 
be  stimulated.  This  stimulus,  or  that 
which  gives  it  the  power  to  contract,  is 
a  nervous  impulse  which  is  sent  along  the 
nerve  fibers  from  the  central  nervous  system.  This  stim- 
ulus acts  upon  the  muscles  and  causes  them  to  shorten  in 
length  and  swell  in  girth. 

71.  Why  Muscles  contract.    The  purpose  of  the  contrac- 
tion of  muscles  is  plain.     By  contracting,  muscles  become 
shorter  and  thicker  and  the  two  ends  are  brought  closer 
together.     Now,  if  one  end  of  a  muscle  is  attached  to  a 
fixed  point  and  the  other  end  is  fastened  to  some  object 
which  is  free  to  move,  the  contraction  of  the  muscle  will 
bring  the  movable  body  nearer  to  the  fixed  point. 

Thus,  the  muscles   cause  the  motion   of  the  parts   to 
which  they  are  attached.    This  motion  in  turn  gives  rise  to 


48  OUR  BODIES  AND   HOW  WE   LIVE 

locomotion  or  other  movements  of  the  body.  In  other 
words,  muscles  by  their  contraction  are  able  to  do  work. 

The  part  of  a  muscle  which  remains  fixed  when  it  con- 
tracts is  called  its  origin. 

The  end  which  is  connected  with  the  movable  part  is  its 
insertion. 

Experiment  15.  To  show  how  muscles  relax  and  contract.  This 
experiment  illustrates  the  contraction  of  the  biceps,  and  is  popularly 
called  "  trying  your  muscle."  Lay  your  left  forearm  on  a  table ; 
grasp  with  the  right  hand  the  mass  of  flesh  on  the  front  of  the  upper 
arm.  Now  gradually  raise  the  forearm,  keeping  the  elbow  on  the 
table.  Note  that  the  muscle  thickens  as  the  hand  rises. 

Reverse  the  act.  Keep  the  elbow  in  position,  bring  the  forearm 
slowly  to  the  table,  and  the  biceps  appears  to  become  softer  and 
smaller,  —  it  relaxes. 

Experiment  16.  Repeat  the  same  experiment  with  other  muscles. 
With  the  right  hand  grasp  firmly  the  extended  left  forearm.  Extend 
and  bend  the  fingers  vigorously.  Note  the  effect  on  the  muscles  and 
tendons  of  the  forearm. 

72.  How  the  Muscles  work  in  Harmony.    A  single  muscle 
rarely  or  never  contracts  alone,  but  always  in  harmony 
with  a  number  of  other  muscles.     Even  the  simplest  move- 
ment we  can  make  requires  the  combined  action  of  several 
muscles  to  carry  it  out.     If  the  movement  is  at  all  difficult, 
such  as  playing  on  the  piano  or  riding  on  the  bicycle,  the 
different  muscles  must  contract  in  a  certain  order  and  with 
a  certain  strength  and  rapidity. 

This  harmonious  working  of  the  muscles  is  spoken  of  as 
muscular  coordination.  Unless  the  muscles  work  in  perfect 
harmony,  the  complicated  movements  will  be  performed 
in  a  clumsy  and  imperfect  way. 

73.  The  Function  of  Tendons.     If  we  bend  the  leg  or 
arm  and  grasp  the  inside  bend  of  the  joint  with  the  hand, 


THE    MUSCLES   AND   HOW  TO   USE   THEM         49 


FIG.  38.     Superficial  Muscles  of  the  Body.     (Front  view.) 


50  OUR  BODIES  AND   HOW  WE   LIVE 

we  feel  the  motion  of  cords  just  beneath  the  skin.  These 
are  the  tendons,  or  sinews;  forming  the  tapering  ends  of 
muscles,  which  are  fastened  to  the  bones. 

Tendons  are  white,  glistening  cords,  or  straps,  which  con- 
nect the  muscles  with  the  bones.  They  are  very  strong 
but  flexible.  Children  often  amuse  themselves  by  getting 
at  the  market  the  leg  of  a  fowl  or  a  rabbit, 
and  moving  the  toes  by  pulling  a  white 
cord  in  the  leg.  This  cord  is  a  tendon. 

Experiment  17.  Tendons  may  be  admirably 
shown  in  the  leg  of  a  fowl  or  turkey.  Obtain  the 
hoof  of  a  calf  or  sheep  with  one  end  of  the  ten- 
don of  Achilles  still  attached.  Test  its  strength. 

Experiment  18.  With  the  thumb  and  fore- 
finger of  the  right  hand,  grasp  firmly  the  inside 
bend  of  the  left  elbow.  Bend  and  extend  the 
left  forearm  vigorously.  The  action  of  the  biceps 
tendon  may  be  readily  studied. 

74.   How  the  Muscles  are  named.    Each 

muscle  has  its  own  name  given  to  it  from 
FIG.  39.  The  Ten-  jts  peculiar  shape,  size,  or  from  the  special 

don  of  Achilles.  ,     .,    ,  ,  ,T  r  ,, 

work  it  has  to  do.  Most  of  these  names 
are  Latin  words,  and  are 'often  hard  to  remember.  Thus, 
some  of  the  muscles  which  help  bend  the  fingers  and  the 
toes  are  called  flexors,  while  those  which  straighten  them 
are  known  as  extensors. 

Some  muscles  have  several  points  of  insertion,  —  for  ex- 
ample, the  two-headed  muscle  (biceps)  and  the  three-headed 
(triceps).  Other  muscles  are  named  from  some  resemblance 
to  figures  in  geometry,  as  the  trapezius  and  rhomboid,  or  from 
the  direction  of  their  fibers,  as  rectus  and  oblique.  Again, 
we  have  in  the  lower  limb  the  tailor's  muscle  (sartorius), 
and  the  sole  muscle  (soleus,  the  sole,  a  fish). 


THE   MUSCLES  AND   HOW  TO   USE   THEM 


75.   A  Few  Muscles  about  the  Head.     We  chew  our  food 
for  the  most  part  with  the  help  of  two  strong  muscles, 

called  the  "chewing  muscles"  (masse- 

ter),  which  move  the  jaws.     They  are 

very  large  and  strong  in  flesh-eating 

animals,  like  the  lion  and  the  tiger. 
Turn  the  head  suddenly  to  one  side, 

and  the  sharp   edge  of  a  muscle  is 

plainly  seen  and 

felt  on  each  side  of 

the  neck  :  one  end 

is  fastened  to  the 

skull,  the  other  to 

the  breastbone  and 

the  collar  bone. 

This  muscle  (sterno- 

cleido-mastoid)  serves 

to  turn  and  to  brace 

the  head. 

Inside  the  cheek 

is  a  flat  muscle,  called  the  "trumpeter's 
muscle."  It  is  largely  developed  in  glass 
blowers  and  in  persons  who  play  on  wind 
instruments. 


FIG.  40.     Tendons  on  the 
Back  of  the  Left  Hand. 


Experiment  19.  With  the  head  slightly  bent 
forward,  grasp  between  the  fingers  and  thumb 
of  the  right  hand  the  edge  of  a  muscle  on  the  FlG 
left,  just  above  the  collar  bone.  Raise  the  head 
and  turn  it  from  left  to  right,  and  the  action  of 
this  important  muscle  (sterno-cleido-mastoid) 

is  readily  seen  and  felt.  In  some  persons,  especially  with  those  who 
are  lean  or  who  have  been  seriously  ill,  this  long,  slender  muscle 
stands  out  in  bold  relief. 


Tendons  on 
the  Top  of  the  Right 
Foot. 


OUR  BODIES  AND   HOW  WE   LIVE 


76.  Some  Muscles  about  the  Shoulder  and  Chest.    The 

large  muscle  on  each  side  of  the  chest  is  fan-shaped,  and 
powerfully  developed  in  strong  men  (pectoralis  major).  It 
helps  draw  the  arm  inward  and  forward. 

The  large,  thick  muscle  covering  the  shoulder  is  thought 
to  resemble  the  Greek  letter  A  (delta).     A  military  officer 


2^.'#%; 


FIG.  42.     Principal  Muscles  on  the  Left  Side  of  the  Neck. 

wears  his  epaulet  over  this  muscle.     The  action  of  the 
two-headed  muscle  (biceps)  which  bends  the  forearm,  and 

the  three-headed  (triceps)  which  straightens  it,  is  familiar 
under  the  name  of  "trying  your  muscle." 

A    three-sided    muscle    (trapezius)    covers  the    shoulder 

blade,  like  a  monk's  hood,  and  helps  move  the  shoulder. 


THE   MUSCLES   AND    HOW  TO   USE   THEM 


53 


77.  Some  Large  Muscles  of  the  Back  and  Legs.  A  very 
broad  muscle  in  the  back  is  the  "climbing  muscle  "  (latis- 
simus  dorsi),  which  serves  to  pull  the  arm  backwards. 

Three  huge  muscles  make  up  the  greater  portion  of  the 
fleshy  mass  in  the  lower  part  of  the  back.  They  move 
the  thigh  backwards  and  help 
to  keep  the  body  erect.  The 
longest  muscle  in  the  body, 
called  the  "tailor's  muscle"  (sar- 
torius),  runs  across  the  thigh  in 
front.  It  helps  us  to  cross  the 
legs. 

Two  strong  muscles  form 
the  largest  part  of  the  calf  of 
the  leg. 

These  muscles  are  constantly 
called  into  use  in  walking,  cy- 
cling, standing,  dancing,  and 
leaping.  They  are  of  great 
strength,  because  in  raising  the 
heel  they  have  to  raise  the 
weight  of  the  body. 

The  tendons  of  these  two 
leg  muscles  unite  to  form  the  tendon  of  Achilles  (Fig.  39). 


FIG.  43.  Some  of  the  Larger 
Muscles  on  the  Back  of  the 
Shoulder  and  the  Arm. 


PHYSICAL   EXERCISE 

78.  Why  we  need  Physical  Exercise.  To  keep  the  body 
in  good  health,  a  certain  amount  of  physical  exercise  should 
be  taken  every  day.  The  reason  for  this  is  plain.  As  we 
have  learned,  the  tissues  contain  a  countless  number  of 
little  cells,  to  which  the  ever-changing  blood,  in  its  cease- 
less current,  brings  oxygen  and  nutriment.  The  tissues 


54 


OUR   BODIES   AND   HOW  WE   LIVE 


take  what  is  specially  suited  to  their  wants,  and  return  the 
waste  matter. 

Now,  in  every  tissue,  especially  in 
the  muscular  tissue,  this  process  is 
hastened  by  action.  Exercise  causes 
more  frequent  changes  in  the  tissues 
and  hence  an  increased  flow  of  blood. 
Muscular  activity  is,  then,  the  chief 
agent  in  bringing  about  these  whole- 
some tissue  changes. 

79.  Effects  of  Exercise  on  the  Mus- 
cles. Muscles  increase  in  size  and 
strength  according  to  the  use  made 
of  them .  The  blacksmith  uses  vigor- 
ously the  muscles  of  his  arms  and 
chest  day  after  day,  hence  they  be- 
come well  developed. 

Let  a  muscle  be  kept  idle  for  some 
time  and  it  loses  in  bulk  and  vigor. 
We  read  of  certain  people  in  India, 
who,  as  an  act  of  worship,  keep  one 
arm  raised  above  the  head  for  many 
weeks.  The  muscles  shrivel  and  the 
arm  becomes  useless. 

If  a  leg  is  broken  and  kept  in 
splints  for  several  weeks,  the  muscles 
become  feeble  and  wasted.  It  is  only 

FIG.  44.     Some  of  the    after  a  £reat  deal  of  exercise  that  the 
Larger  Muscles  on  the    long-idle  limb  regains  its  former  size 

Back  of  the  Thigh.  an(J  vigor. 

Powerful  tendons  at  the  hip  §0.     Effect   Of   Exercise  OH  VariOUS 

and   on  the  back  of  the  .-  ..  .  »        •  i 

knee  are  well  shown.         Organs.     Many  other  organs  besides 


THE    MUSCLES   AND    HOW  TO   USE   THEM 


55 


the  voluntary  muscles  become  more  vigorous  through  exer- 
cise. When  we  exercise  the  heart  beats  more  vigorously 
and  carries  more  blood  to  the  tissues.  Exercise  causes 
the  lungs  to  draw  in  an  extra 
amount  of  fresh  air  and  to  get 
rid  of  more  impure  air. 

Again,  exercise  stimulates  the 
organs  of  digestion,  giving  a 
good  appetite  by  creating  a  de- 
mand for  food.  Hence  the  skin, 
the  lungs,  the  kidneys,  and  the 
intestines  have  to  do  more  work 
to  get  rid  of  the  increased  waste 
products. 

81.  Amount  of  Physical  Exer- 
cise. The  amount  of  exercise 
which  is  necessary  to  keep  the 
body  in  the  best  condition  is  a 
most  important  and  practical 
question.  Too  much  exercise, 
as  well  as  too  little,  is  a  fruitful 
cause  of  ill  health. 

Exercise  beyond  the  point  of 
fatigue  only  does  harm,  while 
judicious  exercise  with  suitable 
rest  is  of  real  benefit. 

It  may  be  laid  down  as  a  safe 
rule  that  a  person  of  average 
height  and  weight,  engaged  in 
study  or  any  other  indoor  or  in- 
active business,  should  have  an  FlTG'  45'  °/\e, of  ,the 

Layers  of  Muscles  of  the 

amount  of  exercise  equivalent  to         Neck  and  the  Back. 


OUR  BODIES  AND    HOW  WE   LIVE 


a  daily  walk  of  five  miles  along  a  level  road.  Growing 
children,  as  a  rule,  take  more  exercise  than  this  ;  while 
most  men  in  the  prime  of  life  working  indoors  take  nothing 
like  this  amount,  and  many  women  take 
even  less.  If  one's  daily  work  is  active 
and  outdoor,  no  additional  exercise  is 
really  necessary.  The  age  is  an  impor- 
tant matter.  A  young  man  or  young 
woman  may  easily  and  safely  take  an 
amount  of  exercise  that  might  do  much 
harm  to  a  person  in  advanced  life. 

Exercise  may  be  varied  in  many 
ways,  — the  more  ways  the  better.  But 
for  the  most  part  it  should  be  taken 
in  the  open  air. 

82.  Time  for  Exercise.  The  best 
time  to  take  exercise  is  about  two 
hours  after  a  meal.  It  is  not' well  to 
do.  hard  work  or  take  severe  exercise 
before  breakfast.  Those  who  go  to 
work  or  study  before  this  meal  should 
first  eat  half  a  slice  of  bread,  or  a  bis- 
cuit, or  even  drink  a  glass  of  milk,  — 
just  enough  to  "stay  the  stomach," 
and  thus  save  the  feeling  of  faintness 
or  "  sinking." 

Just  after  a  full  meal  the  stomach 
is  busily  doing  its  duty.     Exercise  at 
this  time  is  apt  to   retard  its  action 
and  result  sooner  or  later  in  dyspepsia. 
FIG.  46.    A  Whitely     Children  should  not  take  physical  exer- 
Exerciser.  cise  when  they  are  overtired  or  hungry. 


THE   MUSCLES   AND    HOW  TO   USE   THEM 


57 


The  evening  is  not  the  best  time  for  exercise  because  the 
body  is  tired  after  the  labor  of  the  day.  Ordinary  work  or 
moderate  exercise,  as  walking,  is  beneficial  at  almost  any 
time,  except,  perhaps,  just  after  a  full  meal. 

83.  Different  Kinds  of  Exercise.     The  kind  of  exercise 
needed  depends  very  much  upon  one's  daily  occupation. 
Persons  who  sit  at  desks, 

stand  at  counters,  or 
work  in  close  rooms,  as 
clerks,  teachers,  tailors, 
printers,  etc.,  are  prone 
to  diseases  often  traced 
to  lack  of  bodily  exercise 
and  to  foul  air. 

All  well  persons  should 
do  some  work  or  take 
some  exercise  every  day. 
To  get  and  to  keep  vigor- 
ous health  it  is  not  at  all 
necessary  to  increase  the 
size  of  the  muscles  very 
much  or  to  do  great  feats 
of  strength. 

84.  Walking.     Walk- 
ing is  perhaps  the  most 
convenient  and  useful  of 

all  the  exercises  for  most  people.  It  takes  us  into  the 
open  air  and  bright  sunlight.  It  puts  new  vigor  into  the 
work  of  many  important  muscles  of  the  chest,  the  abdo- 
men, and  the  limbs.  With  a  brisk  walk  every  day  while 
in  good  health,  and  taking  care  to  keep  warm  and  dry,  no 
one  need  suffer  from  lack  of  proper  exercise. 


FIG.  47.     School  Girl  practicing  on  a 
Health  Exerciser. 


58  OUR  BODIES  AND   HOW   WE   LIVE 

Running,  leaping,  climbing,  and  other  vigorous  sports  are 
well  enough  if  they  are  not  kept  up  so  long  as  to  cause 
extreme  fatigue. 

85.  More  Vigorous  Exercises.     Vigorous  sports,  such  as 
baseball  and  football,  are  severe  exercises.     Rowing  is  ad- 
mirably suited  to  most  persons  of  either  sex.     Horseback 
and  bicycle  riding,1  swimming,  tennis,  golf,  and   skating 
are  important  helps   toward  bodily  vigor,  and  develop  a 
certain  amount  of  skill  and  adroitness  of  action. 

Certain  sports  also  tend  to  beget  self-reliance,  coolness 
in  danger,  and  a  certain  dignity  and  grace  of  person.  There 
is  hardly  any  one  kind  of  exercise  which,  taken  alone,  is 
able  to  give  even  a  fair  development  of  all  the  muscles. 

86.  Gymnastic  Exercises.     Light    gymnastic   exercises 
are  a  convenient   means  of  developing  muscles  which  are 
not  used  in  ordinary  work  and  games. 

Growing  children  should  be  trained  every  day  at  home 
or  in  school  in  the  use  of  light  wooden  dumb-bells,  light 
clubs,  or  wands.  A  daily  exercise  of  ten  minutes  will  do 


1  It  is  not  the  fashion  at  this  time  to  use  the  bicycle  so  much  for  exercise 
as  in  former  years.  Such  riding,  however,  tends  to  promote  good  health 
fully  as  much  as  any  other  form  of  exercise.  A  bicycle  is  always  ready. 
A  half-hour's  spin  can  be  taken  every  day,  when  the  weather  permits,  by 
even  the  busiest.  A  ride  of  ten  or  even  twenty  miles  a  day,  on  a  fairly 
level  road,  at  a  speed  of  not  more  than  nine  or  ten  miles  an  hour,  is  for  most 
persons  excellent  exercise. 

It  is  especially  as  a  heart  and  lung  exercise  that  wheeling  is  beneficial. 
The  muscular  exercise  involved  in  moderate  and  not  too  rapid  cycling  is 
just  sufficient  to  induce  stronger  contractions  of  the  heart,  and  this  results 
in  increased  activity  of  the  circulation;  for  more  blood  passes  through  the 
lungs  in  a  given  time,  and  so  it  is  aerated  more  efficiently.  At  the  same 
time  the  heart  muscle  is  strengthened  by  its  increased  action.  In  addition, 
the  rapid  movement  in  the  open  air  and  the  exhilaration  of  the  exercise 
increase  the  rapidity  and  depth  of  the  inspirations,  the  lungs  are  expanded 
more  fully,  and  air  is  forced  into  the  smaller  tubes  and  air  chambers. 


THE   MUSCLES   AND   HOW  TO   USE  THEM 


59 


much  to  develop  feeble  and  narrow  chests,  to  check  the 
tendency  to  curvature  of  the  spine  and  round  shoulders  so 
common  with  school  children,  and  to  give  muscular  strength 
and  vigor  to  all  parts  of  the  body. 

87.   Physical  Exercises  in  Schools.     Pupils  should  have 
some  sort  of  physical  exercises  provided  for  them  in  the 


FIG.  48.     Pupils  in  the  Schoolroom  of  a  Lower  Grammar  Grade 
taking  an  Exercise  in  Light  Gymnastics. 

schools,  which  should  be  made  a  part  of  the  regular  course. 
Impure  air,  lack  of  proper  ventilation,  faulty  positions  long 
continued,  and  other  conditions  unfavorable  to  health, 
demand  a  rest  for  overtired  muscles  and  overtaxed  nerves. 
This  is  especially  true  in  large  towns  and  cities,  where 
there  is  often  little  opportunity  for  outdoor  games. 


6o 


OUR  BODIES  AND  HOW  WE   LIVE 


88.  Beneficial  Effects  of  Physical  Exercises  in  Schools. 

Physical  exercises  in  schools,  if  properly  done,  increase  the 
breathing  power  and  quicken  the  action  of  the  heart.  They 
fill  the  arteries  with  pure  blood,  and  distribute  it  with 

increased  energy  to  all  the  tis- 
sues and  organs  of  the  body, 
stimulating  them  to  renewed 
activity.  They  brace  up  the 
whole  system  and  at  the  same 
time  furnish  what  is  very  impor- 
ant, — a  pleasant  recreation. 

NOTE.  —  There   are  several 
excellent   and    inexpensive  "health 
exercisers"  now  on  the  market. 
Handbooks  or  manuals  which  explain 
their  use  and  also  furnish  a  series  of 
physical  exercises  accompany  them. 
FIG.  49.     A  Simple  and  Inexpen-    Booksellers  can  usually  furnish  cat- 
sive  Home  Apparatus  for  Exer-    alogues  of  books,  and  price  lists  of 
cise  on  the  Horizontal  Bar.  the  various  kinds  of  apparatus  for 

physical  culture. 

The  book  above  all  others  which  should  be  read  and  reread  by 
every  one  who  is  interested  in  physical  education  is  Blackie's  How  to 
Get  Strong  and  How  to  Stay  So.  It  is  full  of  stimulating,  wholesome 
advice  and  practical  suggestions  to  those  who  wish  to  practice  health 
exercises  at  home  or  at  school. 

89.  The  General  Effect  of  Alcohol  on  the  Muscles.     We 
have  learned  that  the  nerves  act  upon  the  muscles  and 
make  them  contract  or  relax.     Now,  if  we  drink  a  certain 
amount  of  alcoholic  liquor,  our  muscles  are  acted  upon  in 
a  peculiar  way.     The  nerve  force  that  controls  the  muscles 
is  weakened,  and  they  soon  show  a  lack  of  control. 

The  delicate  movements  which  require  the  long  training 
of  certain  muscles,  as  in  doing  fine  work  and  gymnastic 


THE   MUSCLES   AND   HOW  TO   USE  THEM        6l 

feats,  cannot  be  made.     A  person  may  know  the  right  way 
of  making  each  movement,  and  may  succeed,  after  a  fashion, 


FIG.  50.  Showing  Some  of  the 
Larger  Muscles  on  the  Left 
Side  and  Back  of  the  Body 
that  are  brought  into  Play  in 
descending  a  Ladder. 

From  a  photograph  of  the  living 
model. 


FIG.  51.  Diagrammatic  View 
showing  Some  of  the  Larger 
Muscles  on  the  Left  Side 
and  Back  of  the  Body  as 
exhibited  in  Fig.  50. 

Based  upon  a  photograph  of  the 
living  model. 


62  OUR   BODIES   AND    HOW   WE   LIVE 

in  doing  it  clumsily  ;  but  the  trained  muscles  are  no  longer 
wholly  under  the  control  of  the  will.  If  enough  alcohol  is 
taken,  all  control  of  the  voluntary  muscles  may  be  lost,  and 
deep  breathing  may  be  the  only  sign  of  life. 

90.  Effect  of  Alcoholic  Liquor  upon  Speech.     This  same 
lack  of  control  is  shown  in  the  act  of  speech.     Each  and 
every  word  we  utter  requires  special  movements  of  the 
muscles  of  the  tongue,  palate,  and  throat,  all  acting  in  har- 
mony.    After  drinking  alcoholic  liquor  there  is  less  control 
of  the  muscles:  the  reins  are  slackened,  so  to  speak;  words 
may  be  left  out,  cut  short,  or  misplaced.     According  to  the 
stage  of  intoxication,  the  words  are  clipped,  stammered, 
"  mouthed,"  or  "  thick,"  from  loss  of  control  of  the  muscles 
of  the  tongue  and  throat. 

The  muscles  that  move  the  eyes  do  not  act  in  harmony ; 
hence  the  drunken  man  "sees  double." 

The  degree  of  this  loss  of  muscular  control  and  the  rapidity 
with  which  it  is  produced  vary  with  the  individual,  with 
the  amount,  with  the  kind  of  drink,  with  the  rate  at  which 
it  is  drunk,  and  with  many  other  circumstances. 

91.  Effect   of   Alcohol    on   Muscular    Strength.      Many 
people  honestly  suppose  that  alcohol  gives  them  strength 
for  their  work  and  rests  them  when  they  are  tired.     In  both 
cases  they  are  mistaken.     Instead  of  adding  to  strength 
or  diminishing  weariness,  alcohol  deadens  the  nerves  and 
impairs  the  judgment.      For   it  is  shown   that   when  the 
strength  is  tested  with  a  health  lift  or  other  means,  the 
habitual  user  of  strong  drink  is  found  to  be  weaker  after 
taking  alcoholic  liquor  than  before.     After  the  effect  of  the 
alcohol  has  passed  off   the   feeling  of  weariness  is  more 
intense   than   before,    showing    that    the   alcohol    did    not 
remove  it  but  only  concealed  it. 


THE   MUSCLES   AND   HOW  TO   USE   THEM         63 

92.  Effect  of  repeating  the  Amount  of  Alcohol.     A  repe- 
tition of  the  alcoholic  drink  may  again  create  insensibility 
to  the  fatigued  feeling,  and  the  muscles  may  again  obey 
the  will,  but  only  for  a  briefer  time  than  before.     In  this 
way  the  man  who  could  have  put  forth  just  so  much  strength 
in  an  emergency,  and  could  have  held  out  longer,  accom- 
plishes less  work,  abuses  his  muscles,  and  deludes  his  mind 
by  resorting  to  alcoholic  drinks.     He  has  also  the  injurious 
effects  of  the  alcohol  on  other  parts  of  his  body  to  contend 
with  afterward. 

93.  How  Alcohol    impairs   the    Structure  of    Muscular 
Tissue.     Medical  men  tell  us  that  changes  in  the  muscles, 
called  "  fatty  degeneration,"  are,  in  many  cases,  the  direct 
result  of  the  long-continued  use  of  large  doses  of  alcohol 
and  when  once  the  process  of  degeneration  has  been  set  up 
even  small  doses  appear  to  exert  further  injurious  effects 
upon  the  diseased  muscular  tissues.1 

94.  Effect  of  Tobacco  on  the  Muscles.     Tobacco  tends 
to  weaken  the  nerve  stimulus    which   controls   muscular 

1  It  has  been  demonstrated  on  all  sides,  at  the  forge,  in  the  workshop, 
in  the  field,  on  the  march,  in  the  arctic  region  and  in  the  torrid  zone,  in 
physical  and  in  intellectual  labor,  that  the  spirit  drinker  fails  to  cope  with 
the  temperate  man. — WILLARD  PARKER,  M.D.,  for  many  years  Professor 
of  Surgery  in  the  New  York  College  of  Physicians  and  Surgeons. 

All  medical  authorities  are  agreed  that  in  periods  of  prolonged  physical 
labor,  more  and  better  work  will  be  done  by  men  who  slake  their  thirst  on 
non-intoxicating  drinks  than  by  those  who  drink  large  quantities  of  beer. 
—  British  Medical  Journal. 

The  disadvantageous  effect  of  alcohol  on  persons  performing  mus- 
cular work  is  well  known,  and  the  evidence  is  overwhelming  that  alcohol 
in  small  amounts  has  a  most  deleterious  effect  on  voluntary  muscular 
work.  —  VICTOR  HORSLEY,  in  Lees  and  Rapier  Memorial  Lecture. 

No  amount  of  alcohol,  however  given,  can  increase  the  amount  of 
work  done  in  that  same  period  without  giving  rise  to  very  serious  disturb- 
ances in  other  parts  of  the  body;  indeed,  the  amount  of  work  done  is 
never  really  increased.  —  G.  SIMS  WOODHEAD,  M.D. 


64  OUR   BODIES  AND    HOW  WE   LIVE 

movement.  The  result  is  well  illustrated  in  the  unsteady 
hand  of  the  inveterate  cigarette  smoker  when  he  attempts 
to  draw  a  straight  line  or  do  other  nice  work  which  requires 
precision  of  touch. 

95.  Alcohol  and  the  Operations  of  Armies.  The  armies 
of  the  great  nations  are  often  called  upon  to  undertake  at 
short  notice  long  campaigns  in  almost  every  climate  of  the 
world.  A  modern  army  is  built  up  and  handled  upon  a 
strictly  scientific  plan. 

Many  experiments  have  been  made  upon  large  armies  to 
test  the  value  of  a  daily  ration  of  alcoholic  liquor  to  men 
exposed  to  the  dangers  of  tropical  climates  and  forced  to 
endure  every  variety  of  hardship.  The  results  of  these 
experiments  upon  the  British  armies  during  the  recent 
arduous  Boer  campaigns  in  South  Africa  show  that  the 
soldiers  could  endure  longer  marches  with  no  strong 
drink  than  when  it  was  allowed  them  as  a  part  of  their 
daily  fare.  England's  ablest  generals,  who  handle  their 
armies  upon  a  scientific  basis,  have  strictly  forbidden 
the  supply  of  alcoholic  liquor  to  any  troops  under  their 
command.1 

Experiments  go  to  show  that  while  the  men  were  able 
to  do  an  increased  amount  of  work  for  a  very  short  time 

1  We  learn  that  they  took  this  step  on  two  grounds.  First,  on  the 
ground  that  from  long  experience  they  were  convinced  that  the  physical 
condition  of  the  troops  would,  under  these  conditions,  be  enormously 
improved,  and  the  men  would  have  much  greater  staying  power,  while 
their  dash,  determination,  and  steadiness  would  also  be  increased.  The 
second  ground  appears  to  have  been  that  the  mental  and  moral  stamina  of 
the  troops  would  be  preserved  in  a  far  greater  degree  than  could  possibly 
be  the  case  if  alcohol  were  served  out.  The  result  has  been  that  the  health, 
spirits,  and  conduct  of  the  troops  have  been  the  admiration  of  all  those  who 
have  had  dealings  with  them,  and  this  experiment  on  a  large  scale  has  been 
an  unqualified  success.  —  G.  SIMS  WOODHEAD,  M.D. 


THE   MUSCLES   AND   HOW  TO   USE   THEM         65 


under  the  influence  of  alcohol,  they  did  not  bear  well  sus- 
tained labor  or  exposure.  The  men  of  the  various  regi- 
ments that  were  served  with  liquor  began  their  marching 
well,  but  after  a  short  time  it  was  found  that  they  lagged 


FIG.  52.  Showing  Some  of  the 
Muscles  of  the  Body  that  are 
brought  into  Play  in  Punting. 

From  a  photograph  of  the  living 
model. 


FIG.  53.  Diagrammatic  View  of 
the  Larger  Muscles  of  the  Back 
and  Legs  as  shown  in  Fig.  52. 

Based  upon  a  photograph  of  the  living 
model. 


and  were  surpassed  at  the  end  of  the  day's  march  by  those 
soldiers  who  had  not  been  served  with  a  daily  dram  of 
strong  drink. 

96.  Alcoholic  Liquors  in  the  Navy.  The  modern  battle 
ship  with  its  improved  machinery  and  equipment  and  its 
large  quota  of  men  is  entirely  unlike  the  wooden  men  of  war 


66  OUR  BODIES   AND    HOW  WE    LIVE 

of  a  generation  ago.  Naval  experts  are  making  a  scientific 
study  of  every  detail  which  may  insure  the  best  results. 
Experiments  show  that  in  skill  and  accuracy  of  movement, 
with  power  to  endure,  the  man  behind  the  gun  who  has 
taken  no  alcohol  has  an  advantage  over  one  who  has. 

On  England's  battle  ships  supplies  of  oatmeal  and  water 
placed  in  different  parts  of  the  ship  take  the  place  of  grog 
when  the  fight  is  on.  A  few  years  ago  every  English  sailor 
had  his  double  ration  of  rum  during  battle  to  "  fortify  "  him 
for  his  work. 

For  these  many  years  no  daily  rations  of  alcoholic  liquor 
of  any  kind  have  been  served  to  the  men  on  board  of 
American  men  of  war. 

During  the  recent  war  with  Spain  no  better  work  was 
ever  done  than  by  our  gunners  who  fought  at  Manila  and 
Santiago.  And  yet  the  accuracy  of  the  firing  of  the  great 
guns  in  these  two  battles  was  accomplished  by  men  who 
were  served  freely  with  oatmeal  and  water  instead  of  the 
old-fashioned  double  ration  of  grog.  A  cool,  clear  head  and 
a  steady  hand  are  necessary  for  accurate  firing.  A  modern 
naval  commander  cannot  afford  to  take  chances  with  gun- 
ners who  lack  absolute  control  over  themselves  through 
indulgence  in  rations  of  strong  liquor. 

97.  Effect  of  Alcohol  and  Tobacco  on  Physical  Develop- 
ment. The  main  object  of  physical  exercise  is  to  keep 
our  bodies  in  such  a  condition  that  the  average  amount  of 
working  power  can  be  utilized  at  any  time  without  harm 
to  the  bodily  health.  To  keep  up  this  high  standard  of 
physical  power  and  endurance  we  must  observe  what  have 
been  proved  to  be  the  essentials  to  health. 

One  essential  rule  for  securing  and  keeping  perfect 
health  is  never  to  drink  alcoholic  liquors  or  to  use  tobacco. 


THE   MUSCLES   AND   HOW  TO    USE  THEM         67 

• 

Strong  drink  and  tobacco  will  put  to  naught  the  most 
elaborate  and  costly  system  of  physical  training.  Men 
who  train  athletes,  baseball  and  football  players,  oarsmen, 
and  all  others  who  take  part  in  severe  physical  contests, 
understand  this,  and  rigidly  forbid  their  men  to  indulge  in 
alcoholic  drinks  or  even  to  smoke  or  to  chew  tobacco. 

Experience  has  proved  beyond  all  doubt  that  strong  drink 
is  a  positive  injury,  either  when  men  are  in  training  for 
or  undergoing  contests  demanding  long-continued  physical 
endurance.  No  smoker  who  has  ever  trained  severely  for 
a  race  or  a  game  needs  to  be  told  that  smoking  reduces 
the  tone  of  his  system ;  he  knows  it. 

The  same  law  holds  good  in  the  ordinary  physical  exer- 
cises of  everyday  life.  Alcohol  and  tobacco  act  as  poisons 
to  the  nervous  tissue  which  controls  the  muscles,  and  thus 
lessen  the  amount  of  muscular  power  and  endurance. 

The  demands  of  modern  life  call  for  a  sound  body.  He 
who  indulges  in  alcoholic  drinks  or  tobacco  runs  a  risk  of 
having  a  weak  body  instead  of  a  sound  one.1 

1  Total  abstinence  from  alcohol  and  tobacco  is  required  from  all  competi- 
tors while  in  training  for  athletic  games  and  races.  A  man  who,  after  elec- 
tion as  a  member  of  his  college  crew,  should  be  found  secretly  drinking  beer 
or  smoking  would  be  hissed  out  of  college.  —  H.  NEWELL  MARTIN,  M.D. 

The  tobacco  habit  is  injurious  to  health,  to  scholarship,  and  to  charac- 
ter. It  weakens  the  will,  diminishes  the  power  of  application,  and  lowers 
the  tone  of  thought  and  feeling.  Excessive  smokers  are  uniformly  poor 
scholars.  —  W.  D.  HYDE,  D.D.,  President  of  Bowdoin  College. 

No  railroad,  electric-car,  steamboat,  telegraph,  or  telephone  company,  no 
manufacturing  concern  or  printing  house  will  to-day,  if  they  can  help  it, 
employ  a  man  who  is  a  regular  drinker,  to  say  nothing  of  a  drunkard. 
Safety  first  forced  this  action  on  certain  corporations  and  others  have  fol- 
lowed out  of  economy,  and  it  will  not  be  long  before  no  concern  will  be 
able  to  afford  to  employ  the  man  who  drinks.  —  HENRY  GRAFTON  CHAP- 
MAN, in  The  World's  Work, 


6S  OUR  BODIES  AND  HOW  WE  LIVE 


QUESTIONS  ON  THE  TEXT 

I.  What  is  the  source  of  the  active  powers  of  the  body?     2.  In 
general,   how   are    these   active   powers   manifested?      3.  How  are 
the  bodily  movements  produced?     4.  What  is  muscle?     Illustrate. 
5.  Give  a  few  illustrations  of  the  work  of  muscles.     6.  Upon  what  is 
all  motion  in  our  bodies  dependent?     7.  Name  the  two  great  kinds 
of  muscles.     8.  How  do  these  two  kinds  of  muscles  differ  from  each 
other?     9.  What  is  the   general  build  of   the  voluntary  muscles? 
10.  How  does  voluntary  muscle  look  under  the  microscope  ? 

II.  Describe  the  involuntary  muscles  and  the  appearance  of  their 
tissues  under  the  microscope.    12.  What  is  meant  by  muscular  contrac- 
tion?    13.  What  is  the  object  of  contraction?     14.  What  is  meant 
by  muscular  coordination  ?    15.  What  are  tendons  ?    Illustrate.    16.   In 
a  general  way,  how  are  muscles  named  ?     17.  What  muscles  of  the 
head  can  you  mention  ?  of  the  shoulder  and  the  chest  ?  of  the  back  and 
the  legs?     18.  Why  do  we  need  physical  exercise?     19.  In  general, 
what  is  the  effect  of  exercise  on  the  muscles?    Illustrate.     20.  What 
is  the  effect  of  exercise  on  various  important  organs  ? 

21.  What  can  you  say  about  the  amount  of  physical  exercise  needed  ? 
22.  What  is  the  best  time  for  exercise?  23.  Upon  what  does  the 
kind  of  exercise  depend?  24.  What  can  you  say  about  walking  as 
an  exercise?  about  the  more  vigorous  exercises?  25.  What  is  the 
object  of*  gymnastic  exercises  ?  26.  What  good  results  may  be  due 
to  such  exercises  ?  27.  Why  do  we  need  physical  exercises  in  school  ? 

28.  What   are   some   of   the   beneficial    results   of   such    exercises? 

29.  What  is  the  general  effect  of  alcohol  on  the  muscles  ?     30.  What 
is  the  effect  of  alcoholic  liquor  upon  speech  ? 

31.  Describe  the  effect  of  alcohol  upon  muscular  strength.  32.  What 
is  the  effect  of  taking  alcohol  repeatedly  ?  33.  Explain  the  effect  of 
alcohol  upon  the  structure  of  muscular  tissue.  34.  What  is  the  effect 
of  tobacco  on  the  muscles?  35.  Tell  what  you  can  of  the  effect  of 
alcohol  upon  the  operations  of  armies.  36.  Explain  and  illustrate  the 
effect  of  alcohol  and  tobacco  on  physical  development 


CHAPTER  IV 
FOOD  AND  DRINK 

98.  Why  we  must  have  Food.     In  a  general  way,  the 
body  is  often  compared  to  a  steam  engine  in  good  running 
order.     Our  bodies,  like  the  locomotive,  move  about,  and 
are  warm,  because  a  slow  fire  is  always  burning  in  them. 
This  fire,  like  that  of  the  engine,  needs  fresh  fuel  from 
time  to  time.     Food  is  to  our  bodies  what  coal  and  wood 
are  to  the  engine. 

Without  fuel  and  air  the  fire  in  the  engine  will  go  out. 
So  it  is  with  the  fire  that  is  slowly  burning  in  the  body. 
Without  food  and  air  this  bodily  fire  would  die  out,  and 
we  should  soon  perish.  When  coal  or  wood  is  burned 
smoke  and  ashes  are  formed.  When  food  is  burned  in  the 
body  it  forms  waste  matter,  which  is  got  rid  of  as  speedily 
as  possible. 

99.  How  the  Waste  is  made  Good  by  the  Food  we  eat. 
Everybody    knows    that  a   steam   engine  wears    out    and 
needs  repair  from  time  to  time.     So  it  is  with  the  body. 
Every  beat  of  the  heart,  every  contraction  of  a  muscle, 
and  even  our  very  thoughts,  lead  to  waste.     This  tissue 
change  is  so  complete  that  not  a  particle  of  our  present 
bodies  will  be  ours  a  short  time  hence. 

Something  must  be  taken  into  the  body  to  make  up  for 
this  continued  loss  of  substance.  The  new  material  thus 
used  for  restoring  the  waste  tissues  is  the  food  we  eat.  If 

69 


70  OUR   BODIES   AND   HOW  WE   LIVE 

but  little  or  no  food  is  taken,  or  if  it  is  not  of  the  right 
sort,  the  body  slowly  loses  in  weight.  If  we  try  to  do 
without  food,  we  grow  chilly,  feeble,  faint,  and,  after  a 
time,  too  weak  to  move. 


THE  CLASSIFICATION  OF  FOODS 

100.  Four  Great  Classes  of  Food.     For  convenience  we 
may  divide  food  into  four  great  classes,  to  which  the  name 
food  stuffs,  or  alimentary  principles,  has  been  given.1 

I.  Proteids,  or  nitrogenous  foods 

II.  Starches  and  sugars,  or  carbohydrates 

III.  Fats  and  oils 

IV.  Inorganic,  or  mineral  foods 

101.  Proteids  or  Nitrogenous  Foods.     The  proteids,  fre- 
quently spoken  of  as  nitrogenous  foods,  contain  all  the  mate- 
rials needed  to  build   up  and  repair  the  tissues.     They 
contain  nitrogen,  carbon,  oxygen,  and  hydrogen,  —  which 
form  the  four  essential  elements  of  all  food. 

The  type  of  this  class  of  foods  is  egg  albumin,  familiar 
as  the  white  of  an  egg.  Lean  meat,  the  cheesy  part  or 
curd  of  milk,  peas,  and  beans  are  rich  in  proteids.  Wheat, 
barley,  oats,  and  Indian  corn  also  contain  them. 

The  proteids  are  essential  food  stuffs,  as  they  are  neces- 
sary to  life.  Without  them  the  tissues  of  the  body  would 
gradually  waste  away.  They  supply  the  material  from 

1  To  this  classification  may  be  added  what  are  called  albuminoids,  a 
group  of  bodies  resembling  proteids,  but  having  in  some  respects  a  different 
nutritive  value.  Gelatin,  such  as  is  found  in  soups  or  table  gelatin,  is  a 
familiar  example  of  the  albuminoids.  They  are  not  found  to  any  important 
extent  in  our  raw  foods. 


FOOD   AND   DRINK  /I 

which  new  tissue  is  built  up  or  old  tissue  is  repaired. 
The  burning  up  or  oxidation  of  the  proteids  may  give  rise 
to  heat. 

Experiment  20.  To  test  for  proteid  with  the  white  of  egg.  As 
a  type  of  a  group  of  proteids  let  us  take  the  white  of  an  egg,  or 
egg  albumin.  Place  a  few  drops  of  the  raw  white  of  egg  in  a  test 
tube.  Dilute  it  with  a  tablespoonful  of  water.  Heat  it  over  a  flame. 
The  mixture  will  soon  begin  to  turn  white,  and  become  thicker,  or,  in 
other  words,  to  coagulate. 

Experiment  21.  To  show  grain  albumin  or  gluten.  Take  a  small 
mass  of  dough  made  of  wheat  flour ;  tie  it  in  a  piece  of  cotton  cloth 
and  knead  it  under  water  until  all  the  starch  is  washed  out.  The 
sticky,  stringy  mass  remaining  on  the  cloth  is  gluten,  made  up  of 
albumin,  some  of  the  ash,  and  fats. 

Experiment  22.  To  show  milk  albumin  or  casein.  Heat  a  little 
sweet  milk  in  a  test  tube  or  basin.  It  will  not  coagulate  or  curdle. 
Add  a  few  drops  of  vinegar  and  gently  stir.  The  milk  curdles  and 
separates  into  a  solid  curd  (casein,  the  chief  proteid  of  milk  and  fat) 
and  a  yellowish  fluid  (the  whey). 

102.  Starches  and  Sugars.  The  starches  and  sugars,  also 
called  carbohydrates,  contain  carbon,  hydrogen,  and  oxygen, 
but  no  nitrogen.  This  class  of  foods  forms  a  large  part 
of  all  those  plants  which  are  generally  used  as  articles 
of  diet. 

The  starches  stand  first  in  importance  among  the  vari- 
ous vegetable  foods.  Wheat,  barley,  oats,  rye,  rice,  maize, 
tapioca,  arrowroot,  sago,  potatoes,  etc.,  are  rich  in  starch. 

The  sugars  are  widely  distributed  substances  and  include 
cane,  grape,  malt,  maple,  and  milk  sugars.  Honey  and 
molasses  are  sugar  foods. 

Cellulose  is  a  carbohydrate  that  cannot  be  digested.  Of 
it  the  bark  and  the  fibers  of  fruit,  cereals,  and  vegetables 
are  composed. 


72  OUR  BODIES   AND   HOW  WE    LIVE 

The  carbohydrates  are  burnt  up  in  the  body,  and  set 
free  a  considerable  amount  of  energy.  The  energy  called 
for  in  muscular  work  and  that  which  is  transformed  into 
bodily  heat  come  largely  from  their  oxidation. 

Experiment  23.  To  test  for  starch.  The  test  for  starch  is  a  very 
weak  solution  of  iodine,  the  addition  of  which  to  starch  will  result 
in  a  blue  color.  Pour  a  tablespoonful  of  the  starchy  water  obtained 
from  Experiment  21  into  a  test  tube  and  boil.  The  starch  dissolves 
and  the  solution  becomes  translucent.  If  a  drop  or  two  of  very  weak 
solution  of  iodine  be  added  to  the  cold  starch  solution,  a  blue  color 
will  result.1 

Experiment  24.  Secure  a  specimen  of  the  various  kinds  of  flour 
and  meal,  peas,  beans,  farina,  sago,  cornstarch,  rice,  and  tapioca. 
Boil  a  small  quantity  of  each  in  a  test  tube  for  some  minutes.  Put 
a  bit  of  each  thus  cooked  on  a  white  plate  and  test  for  starch  by 
adding  two  or  three  drops  of  very  weak  solution  of  iodine.  Note  the 
various  changes  of  color,  —  blue,  greenish,  orange,  or  yellowish. 

Experiment  25.  To  test  for  sugar.  The  test  for  sugar  is  Fehling's 
solution  (easily  obtained  of  the  druggist  in  the  form  of  solution  or  in 
tablets).  The  little  white  grains  found  in  raisins  are  grape  sugar 
or  glucose.  Milk  sugar  is  readily  bought  of  the  druggist.  Dissolve 
one  quarter  of  a  teaspoonful  of  grape  or  milk  sugar  in  a  test  tube 
one  quarter  full  of  water.  Add  an  equal  amount  of  Fehling's  solution 
and  bring  the  mixture  to  a  boil.  Note  that  an  orange  or  brick-red 
precipitate  settles  to  the  bottom  of  the  tube.2 

103.  Fats  and  Oils.  The  chief  fats  and  oils  used  as  food 
are  those  of  meat,  eggs,  butter,  and  milk,  also  the  various 

1  The  tincture  of  iodine  cannot  be  diluted  -with  water,  but  it  can  be 
diluted  with  a  saturated  solution  of  potassium  iodide.     A  few  crystals  of 
iodine  may  be  dissolved  in  a  saturated  solution  of  potassium  iodide  to  make 
an  amber-colored  or  pale  brown  solution. 

2  Fehling's  solution  does  not  keep  well.     Make  a  fresh  solution  shortly 
before  it  is  to  be  used.     Before  using,  test  it  by  boiling  a  small  quantity  in 
a  clean  test  tube.     If  it  does  not  keep  its  clean  blue  color,  a  fresh  supply 
should  be  prepared  before  making  any  tests. 


FOOD   AND   DRINK  73 

vegetable  oils.  Most  of  the  breadstuffs  contain  more  or 
less  fat.  The  fats  and  oils  are  rich  in  carbon  and  hydro- 
gen but  contain  little  oxygen.  They  are  more  valuable 
than  the  starches  and  sugars  as  sources  of  energy,  but  the 
latter  are  more  easily  digested. 

104.  Mineral  Salts.  Besides  the  food  stuffs  which  are 
obtained  from  the  animal  and  vegetable  kingdoms,  our 
bodies  must  have  a  certain  amount  of  mineral  matter. 

The  principal  mineral  foods  are  water,  salt,  iron,  lime, 
magnesia,  phosphorus,  and  potash,  which  are  present  both 
in  vegetable  foods  and  in  meat.  Except  water  and  common 
salt,  the  mineral  substances  usually  enter  the  body  only  in 
combination  with  other  food  stuffs. 

Some  of  the  salts  of  food  play  an  important  part  in 
directing  the  chemical  changes  that  take  place  in  the 
tissues  of  the  body.  Others  give  hardness  to  the  bones 
and  the  teeth. 

Experiment  26.  To  test  cereals  for  fat.  Mix  an  even  teaspoonful 
of  Indian  meal,  oatmeal,  or  rye  meal  with  an  equal  volume  of  ben- 
zine. As  its  vapor  is  highly  inflammable,  the  greatest  caution  must 
be  exercised  not  to  handle  it  near  a  flame  or  a  hot  stove.  Stir  care- 
fully and  filter  the  mixture  after  it  has  stood  for  fifteen  minutes  to  get 
rid  of  the  ether  odor.  Evaporate  some  of  the  filtrate  on  a  watch 
glass.  A  greasy  residue  is  left,  which  may  be  shown  by  rubbing  it 
on  a  piece  of  tissue  or  rice  paper. 

Experiment  27.  Evaporate  a  small  quantity  of  milk  to  dryness  in 
an  open  dish.  After  the  dry  residue  is  obtained,  continue  to  apply 
heat ;  observe  that  it  chars  and  gives  off  pungent  gases.  Raise  the 
temperature  until  it  is  red  hot,  then  allow  the  dish  to  cool ;  a  fine 
white  ash  will  be  left  behind.  This  represents  the  mineral  matter 
of  the  milk,  which  does  not  burn. 

The  preceding  experiment  shows  that  a  great  part  of  milk  is  made 
up  of  water.  The  residue  is  the  solid  substance.  The  loss  of  weight 
is  due  chiefly  to  the  loss  of  water. 


74  OUR   BODIES   AND    HOW  WE    LIVE 

105.  Condiments  or  Appetizers.  Certain  substances  are 
used  by  man  to  give  flavor  to  tasteless  foods,  thus  pro- 
ducing an  increased  flow  of  the  digestive  juices  and  a  better 
digestion.  These  substances,  such  as  pepper,  nutmeg, 
cloves,  mustard,  ginger,  and  similar  appetizers,  are  called 
condiments.  Such  stimulating  foods  may  be  used  in  safety 
only  in  moderation. 


IMPORTANT  ARTICLES   OF   DIET 

106.  Different  Kinds  of  Bread.     There  is  no  single  food 
in  the  world  which  meets  so  many  necessary  wants  of  the 
body  as  bread,  "the  staff  of  life."     It  is  made  from  the 
flour  of  wheat,  oats,  rye,  Indian  corn,  and  other  cereals. 

Wheat  flour  gives  us  starch,  sugar,  and  gluten,  —  a  form 
of  proteid  food.  Hence  wheat  bread  contains  nearly  every- 
thing to  support  life  except  fat.  When  we  eat  bread  and 
butter  we  have  a  nearly  perfect  food. 

Corn  meal  is  rich  in  nitrogen  and  has  much  oily  matter. 
It  is  highly  nutritious  and  a  cheap  article  of  food.  Oatmeal 
is  richer  than  flour  in  nitrogen  and  fat,  and  is  therefore 
more  nutritious.  Rice,  though  rich  in  starch,  is  one  of  the 
least  nutritious  of  all  the  cereals. 

107.  Vegetables  and  Fruits.  The  common  or  white  potato 
is  a  most  important  article  of  diet.     Although  it  is  more 
than  two  thirds  water  and  has  little  nutriment,  yet  it  is  easily 
digested.     Sweet  potatoes  are  rich  in  starch  and  sugar. 

Ripe  fruits,  such  as  apples,  pears,  peaches,  strawberries, 
grapes,  bananas,  melons,  oranges,  etc.,  though  not  of  much 
nutritive  value,  are  a  useful  addition  to  our  regular  diet. 
They  are  prized  for  their  agreeable  flavor  and  for  the  salts 
which  they  contain. 


FOOD  AND   DRINK  75 

Sugar  and  molasses  are  both  largely  used  in  cooking. 
Their  nutritive  value  is  about  the  same  as  that  of  starch. 
Peas  and  beans  contain  more  nitrogen  than  any  of  the 
cereals  and  are  as  rich  in  carbon. 

108.  Garden  Vegetables.    Various  kinds  of  fresh  and  juicy 
garden  vegetables,  as  celery,  lettuce,  cucumbers,  radishes,  and 
tomatoes,  are  widely  used  for  their  agreeable  flavor.     They 
give  a  pleasant  variety  and  relish  to  other  articles  of  food. 
They  furnish  little  nutriment  but  are  rich  in  salts. 

109.  Milk  and  Eggs.     Milk  is  the  food  of   all  others 
which  affords  nourishment  in  the  simplest  and  most  con- 
venient form.     This  ideal  food  contains  a  large  quantity  of 
water,  casein,  sugar,  and  fat. 

Eggs  have  a  large  amount  of  nutriment  in  a  small  bulk. 
They  are  usually  easily  digested. 

110.  Meats.     Meats,  for  the  most  part,  consist  of  the 
muscles  of  the  various  animals.     The  most  common  are 
beef,  mutton,  lamb,  veal,  and  pork.     They  are  important 
articles  of  diet  and  as  a  whole  are  easily  digested,  except, 
perhaps,  veal  and  pork.    Fish  is  at  once  a  cheap  and  a  nour- 
ishing food.     Poultry  is  a  useful,  light  article  of  food,  easy 
to  digest,  and  providing  a  great  deal  of  nourishment. 

111.  Mineral  Foods.     There  is  about  a  half  pound  of 
common  salt  in  the  body,  but  we  are  continually  losing  it. 
Tears,  we  know,  contain  salt,  and  it  is  also  found  in  the 
sweat.     Many  people  think  they  do  not  eat  any  common 
salt  because  they  do  not  take  it  by  itself ;  but  they  forget 
that  many  of  the  foods  they  eat,  such  as  bread  and  meat, 
contain  a  little  of  it. 

The  salts  of  potash  are  chiefly  found  in  the  vegetables 
we  eat,  especially  lettuce.  These  salts  are  needed  in  the 
blood.  The  salts  of  lime  make  the  bones  hard  and  strong. 


76  OUR   BODIES  AND    HOW  WE    LIVE 

An  iron  salt  is  found  in  very  small  quantities  in  many  of 
the  foods  we  eat.  It  helps  make  good  blood.  Sulphur  is 
obtained  from  the  yolk  of  eggs. 

112.  Water.  Drink  is  of  just  as  much  importance  as 
solid  food.  Every  one  knows  what  happens  to  plants 
when  they  are  deprived  of  water.  They  first  droop  and 
then  soon  afterwards  wither  and  die.  So  also  it  is  with 
all  animals.  If  they  are  deprived  of  their  drink,  they  also 
droop  and  at  last  die. 

Water  is  the  agent  which  has  been  provided  by  nature  to 
wash  the  food  through  the  living  tissues.  Wild  animals, 
as  well  as  domestic,  take  no  other  drink  but  water.  Pure 
water  is  the  only  drink  that  is  absolutely  essential  for  good 
health.  Thousands  of  human  beings,  following  the  exam- 
ple of  the  lower  animals,  drink  nothing  but  water,  but  yet 
toil  long  and  hard  and  keep  well  and  strong. 

To  be  suitable  for  drinking,  water  should  be  clear,  with- 
out color,  with  little  or  no  taste  or  smell,  and  free  from  any 
great  amount  of  animal  or  vegetable  matter.1 

1  There  is  a  definite  group  of  diseases  which  are  especially  liable  to  be 
spread  by  means  of  bacteria  in  drinking  water.  Among  these  are  such 
diseases  as  typhoid  fever  and  cholera. 

The  appearance  of  the  water  is  by  no  means  conclusive,  for  it  may  be 

beautifully   clear   and    palatable,    yet 
contain  myriads   of  deadl7  bacteria; 

or  k  may  be  muddv and  of  a  disasree- 

able  odor  and  taste,  and  yet  contain 
nothing  of  a  really  harmful  nature. 
The  only  way  by  which  absolute  cer- 
tainty  can  be  had  lies  in  a  chemical 
and  bacteriological  analysis,  repeated 
FIG.  54.  A  Group  of  the  More  Com-  at  regular  intervals. 

mon  Bacteria  found  in  Water.  No  water  at  our  command  upon 

the  surface  of  the  earth  is  absolutely 

free  from  bacteria.     Spring  water  is  the  purest,  and  -water  from  deep  arte- 
sian wells  is  about  equally  pure,     Water  from  lakes  and  reservoirs  is  next 


FOOD  AND   DRINK  fj 

113.  The  Use  of  Water  in  the  Body.     It  is  plain  that  if 
we  take  a  quart  or  more  of  water  every  day,  nearly  an  equal 
amount  must  be  thrown  out  from  the  body.     Some  of  it 
steams  away  with  the  breath.     More  of  it  passes  through 
the  pores  of  the  skin  as  perspiration,  and  still  more  is 
drained  away  through  the  kidneys.     Thus,  water  drains  off 
a  great   deal  of  waste  matter  from  the  body.     A  great 
amount   must   be  supplied,  especially  in  hot   weather,  to 
make  good  this  loss. 

This  topic  is  more  fully  treated  in  Chapter  IX. 

114.  Drinking  in  Hot  Weather.     One  of  the  most  com- 
mon of  all  drinks  used  in  this  country  is  ice  water.     The 
temptation  to  drink  freely  of  it  in  hot  weather  is  rarely 
resisted.      It  should  be  sipped  slowly  and  only  a  small 
amount  taken  at  a  time. 

It  is  a  dangerous  thing  to  drink  ice  water  in  great  gulps 
when  overheated.  The  proper  way  is  to  rinse  the  mouth 
and  take  slowly  a  few  swallows.  It  is  always  to  be  remem- 
bered that  very  little  cold  water  is  really  needed  to  quench 
thirst  and  refresh  the  heated  body.1 

115.  Refreshing  Drinks.     The  greater  portion  of  every 
drink  is  water ;  but,  in  various  ways,  other  substances  are 
mixed  with  the  water  to  give  it  a  pleasant  taste. 

Many  kinds  of  refreshing  drinks,  made  up  for  the  most 
part  of  flavored  water  slightly  charged  with  carbonic  acid 

in  purity,  and  water  derived  directly  from  flowing  streams  and  rivers  is  most 
likely  to  contain  these  organisms  in  greatest  numbers.  The  most  danger- 
ous water  for  drinking  purposes  is  that  of  rivers  which  have  been  contami- 
nated in  any  way  by  sewage  material,  a  condition  of  things  true  of  the 
water  used  in  some  cities.  —  H.  W.  CONN'S  Bacteria,  Yeasts,  and  Molds, 

1  When  overheated,  and  before  drinking  cold  water,  it  is  always  prudent 
to  pour  water  slowly  over  the  inside  of  each  wrist  (over  the  radial  artery), 
or  allow  it  to  run  from  the  faucet.  This  helps  greatly  to  cool  and  refresh 
the  body  and  to  lessen  the  amount  of  water  needed  to  quench  thirst. 


78  OUR  BODIES  AND   HOW  WE   LIVE 

gas,  are  widely  used.  They  are  known  by  a  great  variety 
of  names,  as  ginger  ale,  soda  water,  and  the  like.  When 
taken  in  moderation  they  are  harmless.  Tea,  coffee,  and 
chocolate  are  the  more  common  artificial  drinks. 

116.  The  Effect  of  drinking  Tea  and  Coffee.     Tea  and 
coffee  have  little   or   no  value  as  foods.     Some  persons 
cannot  drink  even  a  single  cup  of  coffee  or  tea  without 
feeling   worse    for   it :    headache,    indigestion,    heartburn, 
wakefulness  at  night,  and  constipation  are  the  most  com- 
mon after  effects.     Strong  tea  should  never  be  used. 

Hard-working  women  and  others,  from  choice  or  neces- 
sity, too  often  make  their  meals  of  dry  toast  and  several 
cups  of  strong  tea.  Taken  in  excess,  tea  may  disturb 
the  action  of  the  heart  and  produce  the  peculiar  beating 
known  as  palpitation. 

117.  Cooking.     The  art   of   cooking  and   serving  food 
well  plays  an    important    part   in  the   matter  of   health, 
and  thus  of  comfort  and  happiness.     Food  is  more  readily 
chewed  and  more  easily  digested  after  it  is  properly  cooked. 
Thus,  raw  meat  is  tough  and  tenacious,  but  may  become 
tender  and  palatable  after  it  is  cooked.     Vegetables  and 
cereals  are   softened   by   cooking  so  that  they  are  more 
easily  acted  upon  'by  the  digestive  fluids.     Cooking  also 
brings    out    flavors   in   food  which   stir  the  appetite  and 
promote  the  flow  of  digestive  fluids. 

Again,  cooking  kills  any  minute  parasites  or  germs  of 
disease  that  may  exist  in  raw  food. 

Thus,  proper  cooking  not  only  adds  to  the  comfort  and 
health  of  daily  living  but  also  removes  some  important 
causes  of  disease. 

Every  young  person  should  be  taught  to  cook  properly 
a  few  of  the  more  common  and  important  articles  of  food. 


FOOD   AND   DRINK  79 


QUESTIONS  ON  THE  TEXT 

I.  To  illustrate  work,  waste,  and  repair,  how  may  we  compare  our 
bodies  to  a  steam  engine  ?     2.  How  is  the  waste  made  good  in  the 
steam  engine,  and  also  in  our  bodies  ?     3.  What  are  the  four  great 
classes  of  foods?     4.  What  chemical  elements  do  the  proteid  foods 
contain?      5.  Why  are  the  proteids  necessary  to  life?      6.   In  what 
articles  of  diet  do  we  find  proteids  ?     7.  What  chemical  elements  do 
the  starches  and  sugars  contain  ?     8.  Give  some  familiar  examples 
of  this  class  of  foods.     9.  In  what  articles  of  diet  are  the  fats  and 
oils  found  ?     10.  What  is  meant  by  the  mineral  salts  ? 

II.  What  is  meant  by  condiments?   Illustrate.   12.  What  can  you  tell 
of  the  importance  of  bread  as  an  article  of  diet  ?     13.   Mention  some 
vegetables  and  fruits  that  are  used  for  food.     14.  What  garden  vege- 
tables are  commonly  used  for  food?     15.  Why  are  milk  and  eggs 
important  articles  of  diet?     16.  What  are  some  of  the  principal  food 
materials  of  animal  origin?     17.  What  is  the  use  of   the  mineral 
foods?     18.  Why  is  water  important  as  an  article  of  diet?     19.  What 
properties  must  water  possess  in  order  to  be  fit  for  use  as  an  article 
of  diet  ?     20.  What  becomes  of  the  water  that  is  taken  into  the  body  ? 

21.  What  can  you  say  of  the  use  of  ice  water?  22.  Of  the  use  of 
other  refreshing  drinks?  23.  Explain  in  a  general  way  the  harmful 
effects  of  drinking  tea  and  coffee.  24.  What  are  the  objects  of  cook- 
ing food?  25.  Why  is  the  knowledge  of  proper  cooking  necessary 
to  health  ? 

NOTE.  —  A  series  of  most  interesting  experiments  may  be  planned 
by  teachers  and  pupils  on  the  subject  of  food  and  drink.  It  should 
be  our  object  to  understand  the  few  general  principles  which  underlie 
the  matter  of  our  daily  food.  We  should  aim  to  become  familiar  with 
the  principal  substances  contained  in  the  four  great  classes  of  foods. 
We  can  do  this  by  exhibiting  specimens  and  by  experiment. 

The  teacher  should  show  specimens  of  the  various  cereals,  starches, 
sugars,  fats,  oils,  etc.,  which  have  been  carefully  collected  and  kept 
for  class  use  in  wide-mouthed  bottles  bought  at  the  drug  store.  Small 
radish  or  pickle  bottles  will  answer  every  purpose.  Each  specimen 
should  be  neatly  labeled  with  its  exact  name. 


CHAPTER  V 
ORIGIN  AND  NATURE  OF  FERMENTED  DRINKS 

118.  Healthful  Juices  from  Ripe   Fruits.      If    we    are 
thirsty  and  we  do  not  wish  to  drink  water,  we  can  relieve 
our  thirst  by  the  juice  of  ripe  fruits,  like  grapes,  oranges, 
apples,  pears,  and  peaches.     These  fruit  juices  are  made 
up  largely  of  water  sweetened  with  sugar  which  nature 
prepares  in  them  as  the  fruit  ripens,  and  each  is  flavored 
according  to  its  kind.     Such  juices,  as  we  use  them  fresh 
from  the  fruit,  are  refreshing  and  healthful. 

Now,  if  we  crush  one  of  these  ripe  fruits  and  pour  a  little 
of  its  juice  into  a  tumbler  and  let  it  stand  in  the  air  of 
ordinary  temperature,  we  all  know  what  will  happen.  It 
will  remain  a  healthful  drink  for  a  few  hours  only.  A  scum 
appears  on  the  surface,  bubbles  begin  to  rise,  and  there  is 
an  unpleasant  taste  to  the  liquid.  In  brief,  we  say  that  the 
fruit  juice  has  turned  sour  or  has  begun  to  "work." 

119.  Decay  a  Great  Law  of  Nature.     All  animal  and 
vegetable  matter,  as  we  have  learned  iri  the  Introduction, 
is  made  up  of  various  simple  substances,  —  gases,  liquids, 
and  solids.     Now,  it  is  one  of  nature's  laws  that  when  plant 
or  animal  matter  ceases  to  live,  the  different  substances 
composing  it  shall  be  set  free  for  use  again  in  forming 
new  combinations.     A  living  thing,  like  a  plant  or  animal, 
dies   and   is  exposed  to  the   contact   of  air.     To  the  life 
which  has  left  it,  succeeds  life  under  other  forms. 

80 


NATURE   OF    FERMENTED   DRINKS 


8l 


When  we  see  meat  or  vegetables  spoiling,  bread  or 
cheese  molding,  fruit  rotting,  or  milk  turning  sour,  we 
simply  see  a  few  of  the  countless  examples  of  nature's 
great  law  of  decay.  This  "  working "  or  souring  only 
represents  the  first  step  of  the  return  to  the  atmosphere 
and  to  the  soil  of  all  that  has  lived. 

120.  Fermentation.  The  "  working,"  or  fermenting,  as 
it  is  called,  of  sweet  fruit,  plant,  or  other  vegetable  juices, 
which  takes  place  very  soon  after  they  are  pressed  out,  is 
another  and  familiar  ex- 
ample of  the  same  wise 
provision  of  nature.  This 
last  process  is  not  accom- 
panied by  foul -smelling 
odors,  as  are  most  of  the 
others,  but  by  a  peculiar 
bubbling  of  the  liquid 
caused  by  the  escaping 
gases ;  hence  the  name 


FIG.  55.  Showing  the  Comparative 
Size  of  Molds  (a),  Yeast  (b  and  <:), 
and  Bacteria  (d}. 


"  fermentation,"  which  is  taken  from  a  Latin  word  meaning 
to  boil. 

Fermentation  in  its  widest  sense  includes  the  changes 
going  on  in  the  putrefying  meat,  the  molding  cheese,  and 
the  rotting  fruit,  as  well  as  in  the  fermenting  fruit  juice. 
They  are  all  forms  of  decomposition  that  set  free  the  sim- 
pler substances  composing  animal  and  vegetable  matter. 
For  all  these  one  law  holds  good.  It  is  this  : 

Fermentation  entirely  changes  the  nature  of  the  substance  fer- 
mented. 

121.  The  Importance  of  Bacteria  in  Nature's  Work  of 
Decay.  What  causes  all  these  various  processes  of  de- 
composition ?  Are  plants  and  animals  so  constructed  that 


82  OUR  BODIES  AND    HOW  WE   LIVE 

when  they  have  served  their  purpose  they  fall  to  pieces  of 
themselves,  or  from  the  action  of  the  air,  as  was  once  sup- 
posed ?  No ;  the  microscope  has  revealed  to  us  whole 
tribes  and  families  of  minute  living  forms  known  as  yeast, 
mold,  and  bacteria.  It  is  the  special  work  of  these  tiny 
organisms  to  change  dead  animal  and  vegetable  matter 
into  useful  substances.  In  brief,  bacteria  prepare  food 
for  all  the  rest  of  the  world. 

Were  it  not  for  these  countless  myriads  of  living  organ- 
isms, the  whole  surface  of  the  earth  would  in  time  be  cov- 
ered with  dead  trees  and  other  lifeless  bodies,  and  there 
would  be  no  simple  substances  left  out  of  which  to  build 
up  new  ones.  Were  all  living  forms  that  are  silently  at 
work  bringing  about  these  wonderful  results  destroyed, 
life  upon  the  earth  would  be  impossible. 

122.  Living  Forms  that  cause  Disease.  Among  these 
minute  living  forms  are  some  that  do  not  even  wait  for  a 

plant  or  animal  to  die 
before  attacking  it. 
Such  are  the  disease 
germs  which  are  invisi- 

y,         .vrv>,- - .-",  - ,",'  •»  •>'-« »>,\V'-»".v  ' ;' 

:V^';v  V^^vU'^^v     ble  to  the  naked  eye  and 

^  >!»«.»_  •   *    .*  '  .  * . .  t  ^  \  .  — >  * " :  v-  »-*-  -  * 

of  an  infinite  variety  of 
form  and  manner  of  life. 
They  lurk  in  the  air  we 
breathe  ;  they  occur  in 


FIG.  56.    Showing  the  Effect  of  Variations 

in  Temperature  on  Bacteria  Growth.         the    water    we    drink; 

a,  a  single  bacterium ;  b,  its  progeny  in  twenty-     they     are    found    in    OUr 
four  hours  at  50° ;  c,  its  progeny  in  twenty-  j  j  fc    g  u         j         read       t Q 

four  hours  at  70°.  . r  r    J  J 

cause    sickness   if    they 

gain  access  to  our  bodies,  unless   our  bodies  are  strong 
enough  to  resist  them. 


NATURE   OF   FERMENTED   DRINKS  83 

123.  Bacteria,  the  Active  Agents  of  Fermentation.     The 

myriads  of  living  creatures  that  play  this  part  as  active 
agents  in  the  process  of  fermentation  are  grouped  under 
the  family,  or  generic,  name  of  bacteria. 

The  words  germs,  microbes,  and  microorganisms  are  often 
used  with  the  same  meaning  as  the  term  "bacteria." 

Bacteria  are  very  low  forms  of  plant  life,  of  which 
there  are  many  varieties.  They  are  roughly  divided  into 
groups,  according  as  they  are  spherical,  rodlike,  or  spiral 
in  shape.  It  is  now  known  that  a  large  number  of  species 
of  bacteria  exist,  but  that  some  forms  which  have  been 
described  are  simply  stages  in  the  life  history  of  other 
forms. 

It  is  impossible  for  us  to  realize  how  small  these  agents 
of  fermentation  are.  Some  of  the  rod-shaped  are  from 
a  twelve-thousandth  to  an  eight -thousandth  of  an  inch 
long,  and  average  about  a  fifty-thousandth  of  an  inch  in 
diameter.  It  has  been  calculated  that  two  hundred  and 
fifty  millions  of  minute  organisms  would  not  weigh  more 
than  one  milligram  (Sees.  419-426). 

124.  Mold.     To  this  great   family   of   bacteria    belong 
certain  low  forms  of  plant  life  familiar  as  mold.     This  is  a 
low  form  of  fungous  growth  which  is  often  seen  upon  decay- 
ing wood  or  old  leather.     It  is  this  fine,  furlike  coating 
which  spoils  our  bread  and  cheese,  causes  our  sauce  to 
sour,  and  our  fruit  to  rot. 

The  work  of  some  kinds  of  molds  may  be  apparent  to 
the  eye,  as  in  the  growths  that  form  on  old  leather  and 
on  stale  bread  and  cheese.  The  work  of  other  kinds  of 
molds  goes  on  unseen,  as  when  acids  are  formed  in  stewed 
fruits.  One  kind  of  mold  devours  our  preserves;  another 
turns  our  bread  sour.  One  kind  is  nourished  at  the 


84  OUR  BODIES  AND   HOW  WE   LIVE 

expense  of  our  fruits ;  and  another  develops  itself  on 
paper,  on  the  inside  of  books,  and  on  their  bindings, 
when  they  come  in  contact  with  a  damp  wall.  Some  forms 
of  skin  disease,  like  ringworm,  are  caused  by  the  growth 
of  this  microscopic  plant  on  the  skin. 


FIG.  57.     A  Piece  of  Bread  upon  which  One  of  the  Common  Molds, 
known  as  Mucor,  is  growing. 

125.  Different  Forms  of  Fermentation.  There  is  no  one 
particular  form  of  bacteria  which  can  be  called  the  micro- 
organism of  fermentation,  but  there  are  a  number  of  fer- 
mentations each  started  by  some  special  form  of  agent. 
We  must  remember,  however,  that  fermentation  nearly 
always  consists  of  a  process  of  breaking  down  of  complex 
bodies,  like  sugar,  into  simpler  ones,  like  alcohol  and  car- 
bonic acid.  Of  these  fermentations  we  have  the  alcoholic, 
by  which  alcohol  is  produced  ;  the  acetous,  by  which  wine 
absorbs  oxygen  from  the  air  and  becomes  vinegar;  and  the 


NATURE   OF    FERMENTED   DRINKS 


lactic,  which  sours  milk.  The  ammonia  smell  about  stables 
is  caused  by  another  form  of  fermentation  due  to  the  break- 
ing down  of  compounds  of  nitrogen  into  ammonia. 

When  the  word  "  fermentation  "  is  used  alone,  alcoholic 
fermentation  is  usually  meant. 

126.  Alcoholic  Fermentation.  The  fermentation  of  sweet 
fruit,  plant,  or  other  vegetable  juices,  composed  largely  of 
water  containing  sugar  and  flavoring  matters,  is  based  upon 
the  growth  of  a  class  of  microscopic  plants  commonly  known 
as  yeasts.  This  ceaseless  action  of  minute  forms  of  plant 
life  is  closely  al- 
lied to  that  of 
bacteria. 

There  are  many 
varieties  of  the 
yeast  plant  which 
grow  on  the  sur- 
faces and  stems 
of  fruit  as  it  is 
ripening.  While 
the  fruit  remains 
whole  these  germs 
have  no  power  to 
invade  the  juice, 


FIG.  58.     Showing  One  of  the  More  Common 
Molds  found  on  Fruit  and  Bread. 


The  tiny  stalks  grow  vertically  into  the  air.     The  end  of 
and    even    When       each  thread  swells  into  a  small  round  knob,  from  the 


inside  of  which  hundreds  of  minute  bodies,  called  spores, 
burst.     At  a  is  seen  a  large  knob  filled  with  spores. 


the  skins  are 
broken  the  condi- 
tions are  less  favorable  for  their  work  than  for  that  of  the 
molds,  which  are  the  cause  of  the  rotting  of  fruit. 

But  when  fruit  is  crushed  and  its  juice  pressed  out,  these 
yeast  germs  are  carried  into  it  and  cause  a  breaking  up  of 
the  sugar  and  a  rearrangement  of  its  elements. 


86  OUR   BODIES   AND   HOW  WE    LIVE 

Two  new  substances  are  formed  out  of  the  material 
that  composed  the  sugar.  One  substance  is  carbon  dioxide, 
a  gas  that  passes  up  and  out  of  the  liquid  in  the  form  of 
bubbles. 

The  other  substance  is  alcohol,  a  liquid  and  a  poison,  which 
remains  in  the  fermenting  fluid. 

127.  Change  wrought  by  Alcoholic  Fermentation.    It  is  a 
law  of  nature  that  fermentation  changes  the  character  of 
the  substance  fermented.     Fresh  fruit  juice  that  has  not 
begun  to  ferment  is  good  and  wholesome.    With  the  begin- 
ning of  fermentation  its  nature  begins  to  change.     When 
all,  or  nearly  all,  of  the  sugar  in  the  fruit  juice  has  been 
changed  to  alcohol,  the  effect  of  the  wine  thus  resulting 
upon  the  person  who  drinks  it  will  be  very  different  from 
the  effect  of  the  same  quantity  of  fresh  fruit  juice. 

A  great  variety  of  plant  structures,  such  as  the  juice  of 
ripe  grapes,  pears,  apples,  and  other  fruits,  and  infusions  of 
barley,  corn,  rye,  wheat,  and  other  grains  have  been  used 
by  man  in  the  manufacture  of  alcoholic  beverages.  But 
whatever  the  substance  used,  whenever  a  sweet  liquid  is 
made  to  undergo  alcoholic  fermentation  the  result  is  a 
liquid  containing  alcohol  and  therefore  dangerous  for  use 
as  a  beverage. 

128.  Wine.     One  of  the  most  common  alcoholic  bever- 
ages is  wine,  made  chiefly  from  the  juice  of  grapes.    Home- 
made wines  are  often  made  from  the  juice  of  currants, 
blackberries,  tomatoes,  and  other  fruits  rich  in  sugar.     As 
the  juice  is  pressed  out  of  the  crushed  fruit,  the  yeast  fer- 
ments which  are  in  the  air  as  well  as  on  the  stems  and 
skins  are  washed  into  a  vat.      Here  the  ferments  bud  and 
multiply  rapidly  as  fermentation  begins.     In  a  short  time 
the  sugary  juice  that  was  sweet  and  wholesome  while  in 


NATURE   OF    FERMENTED    DRINKS 


the  fruit  has  been  changed  into  a  liquid  containing  carbon 
dioxide  which  escapes  as  bubbles  of  gas  into  the  air,  and 
alcohol  which  remains  in  the  fluid.1 

Most  wines  after  fermentation  contain  from  five  to  four- 
teen per  cent  of  alcohol.  When  the  fourteen  per  cent 
limit  is  reached  these 
germs  are  unable  to 
continue  their  work. 

129.  The  Danger 
from  Wines.  One 
of  the  gravest  dan- 
gers of  wine  drink- 
ing is  the  power 
which  the  alcohol  in 
it  has  to  create  a 
craving  for  more  and 
stronger  alcoholic 
beverages.  We  must 
remember  that  the 
power  of  alcohol  to 
create  this  craving 
is  not  affected  by  the 
quantity  in  any  given 
liquor.  It  is  claimed, 
for  instance,  that  the 
light  table  wines,  be- 
cause they  contain  a  smaller  amount  of  alcohol  than  others, 
are  less  harmful ;  but  the  alcohol  in  even  the  lightest 

1  The  ferments  have  no  power  of  themselves  to  penetrate  the  unbroken 
skin  of  the  healthy  fruit.  —  Louis  PASTEUR,  M.D. 

The  bloom  on  the  outside  of  the  skin  of  the  grape  is  full  of  ferment 
germs  awaiting  an  opportunity  to  feed  upon,  and  so  to  ferment,  the  sugary 
juice  inside.  —  W.  T.  SEDGWICK,  PH.D. 


d  e 

FIG.  59.  Showing  a  Bit  of  Common  Yeast 
Cake  when  mixed  with  Water  and  exam- 
ined under  the  Microscope. 

Very  highly  magnified. 

There  are  large  numbers  of  minute  oval  bodies, 
inside  of  which  may  commonly  be  seen  one  or 
more  smaller  bodies  known  as  vacuoles,  shown 
in  a  and  b.  c  shows  a  nucleus,  «,  inside  of  the 
yeast  cell ;  d  shows  a  budding  cell  with  the  nu- 
cleus dividing;  e  shows  the  cell  divided,  the  new 
cell  containing  a  bit  of  the  old  nucleus. 


88  OUR  BODIES  AND   HOW  WE   LIVE 

table  wines  has  power  to  create  the  alcoholic  craving.  The 
theory  that  the  use  of  light  wines  will  prevent  the  use  of 
stronger  drinks,  and  so  diminish  drunkenness,  is  disproved 
by  the  history  of  countries  where  such  wines  have  come 

into  general  use.1 

130.  Beer.  Certain  fer- 
mented drinks  are  called 
malt  liquors.  These  are 
beer,  ale,  and  porter,  which 
are  made  from  barley  and 
other  grains.  By  keeping 
the  grain  warm  and  moist 
until  it  is  sprouted,  the  starch 
is  turned  to  sugar.  This  is 
FIG.  60.  Organisms  found  upon  the  done  because  the  yeast  germ 

Skin  of  a  Grape  and  concerned  in     ^     ^    ^  ^^ 

the  Fermentation  of  Wine.  .  .  . 

Heat  is  applied  to  kill  the 

sprouts,  so  that  the  budding  plant  will  not  use  up  the  sugar 
as  food.  The  grain,  then  called  malt,  is  ground  or  mashed, 
and  soaked  in  water.  To  the  sweet  liquid  thus  obtained  is 
added  the  yeast  ferment  and  hops. 

Let  us  now  remember  what  takes  place.  The  yeast  sets 
up  alcoholic  fermentation,  which  changes  the  sugar  of  the 
wort  to  alcohol  and  carbon  dioxide.  The  gas  escapes  in 
bubbles,  producing  a  froth  on  the  top  of  the  fermenting 
vat.  The  alcohol  does  not  escape  but  remains  in  the  beer, 
making  it  a  harmful  drink. 


1  Not  the  least  of  the  evils  affecting  France  is  her  consumption  of  alco- 
hol. It  is  known  that  the  honest  glass  of  light  wine  which  used  to  meet 
the  wants  of  the  ordinary  Frenchman  is  now  supplemented  with  spirit  in 
all  forms,  and  that  France  is  first  of  all  countries  in  the  amount  of  alcohol 
which  is  consumed.  —  London  Lancet. 


NATURE   OF   FERMENTED    DRINKS 


Some  kinds  of  beer  contain  only  a  small  percentage  of 
alcohol,  but  these  are  often  taken  in  such  large  quantities 
that  the  user  gets  as  much  alcohol  as  he  would  in  smaller 
amounts  of  stronger  drinks. 

131.  The  Food  Value  of  Beer.  The  drinking  of  beer 
does  not  give  strength  for  work,  but  on  the  other  hand 
tends  to  make  people  dull,  heavy,  stupid,  and  unfit  for  hard 
and  continued  manual  or  mental  labor.  Because  both  beer 
and  bread  are  ^  often  made  from  the  same  cereals,  the 
former  has  been  called  "liquid  bread." 

There  is  a  popular  saying  that  "  where  the  brewery  is, 
no  bakery  is  needed."  As  a  matter  of  fact,  chemists 
tell  us  that  the  best  beer  is  more  than  nine  tenths  water, 
from  four  to  five  per  cent  alcohol,  and  that  scarcely  two 
per  cent  is  really  food.  A  healthy  grown  person  would 
have  to  drink  about 
two  gallons  of  beer 
every  day  to  get 
the  same  amount  of 
nutriment  he  would 
get  from  a  few  slices 
of  bread.  The 
harmful  effect  of  FIG.  61. 
drinking  this  large 
amount  of  beer 
daily  would  quickly 
show  itself.1  The 
food  value  of  a  glass 
or  two  of  beer  is  of  so  little  importance  that  it  is  scarcely 
worthy  of  mention. 


Growing  Yeast  Cells,  showing  Method 
of  budding  and  forming  Groups  of  Cells. 

Each  bud  appears  as  a  little  swelling  on  the  side  of  the 
larger  cell,  as  seen  in  a  and  b.  In  c  the  little  bud 
has  grown  to  be  nearly  as  large  as  the  parent  cell. 
The  little  buds  grow  one  after  another,  making 
irregular  shaped  groups,  as  shown  in  d. 


1  The  constant  use  of  beer  every  day  gives  the  system  no  recuperation, 
but  steadily  lowers  the  vital  forces.  —  Scientific  American. 


90  OUR   BODIES   AND   HOW   WE    LIVE 

Remember,  then,  from  an  economical  point  of  view,  that 
beer  is  in  no  sense  a  nutritive  food  nor  in  any  respect  a 
prudent  food.1 

132.  Drinking  Beer  in  Place  of  Ardent  Spirits.     It  is 
claimed  by  some  people  who  realize  the  evil  results  of 
drinking  wine,  whisky,  gin,  and  brandy,  that  the  drinking 
of   light   beers   in  place  of   the  stronger  beverages  does 
much  to  diminish  the  use  of  ardent  spirits.     This  is  the 
question  in  plain  words  :  Does  the  drinking  of  more  beer 
really  mean  the  consumption  of  less  ardent  spirits  ?     Not 
at  all.     Physicians  and  students  of  domestic  science  who 
have  given  much  study  to  the  problem  most  emphatically 
say,  No  !     They  claim  that  no  habitual  user  of  ardent  spirits 
was  ever  saved  from  the  ill  effects  of  alcoholism  by  the 
drinking  of  beer.2 

133.  The  Physiological   Effect  of   Malt  Liquors.     The 
habitual  beer  drinker  often  looks  the  picture  of  health,  and 
perhaps  is  inclined  to  boast   of  the  healthfulness  of  his 
favorite  beverage.     The  testimony  of  physicians  and  life- 
insurance  experts,  however,  is  that  the  habitual  beer  drinker 
is  not  so  physically  strong  and  well  nourished  as  would 
appear  at  the  first  glance.     The  flesh  is  not  apt  to  be  firm 

1  Let  a  man  drink  much  beer,  enough  to  make  the  amount  of  nourish- 
ment in  it  of  value,  and  the  other  influences  produced  by  such  a  quantity 
will  become  manifest  to  such  a  degree  as  to  cast  the  factor  of  nourishment 
in  the  background.    If  he  drinks  little  beer,  the  food  value  is  not  appreciable. 
—  PROFESSOR  ROSENTHAL,  Erlangen,  Germany. 

2  One  of  the  worst  features  of  the  poisonous  characteristics  of  alcohol  is 
its  power,  even  in  small  quantities,  to  create  a  craving  for  itself  that  becomes 
irresistible.     It  is  therefore  the  nature  of  wine  to  lead  to  an  increasing  use 
of  alcohol.  —  H.  NEWELL  MARTIN,  M.D. 

One  can  accustom  oneself  more  readily  to  the  drinking  of  beer  than  of 
any  other  intoxicant,  and  no  other  so  rapidly  destroys  the  appetite  for  nor- 
mal food  and  nourishment.  —  GUSTAV  VON  BUNGE,  M.D.,  Professor  of 
Physiological  Chemistry  in  the  University  of  Basel,  Switzerland. 


NATURE   OF    FERMENTED    DRINKS 


and  hard,  and  the  fair  outside  appearance  is  mainly  due  to 
an  unnatural  deposit  of  fat  in  most  of  the  tissues,  especially 
around  the  heart  and  kidneys. 

Such  a  person's  physical  condition  is  peculiarly  deceptive 
at  first,  and  is  often  subject  to  a  sudden  collapse  at  the  first 
touch  of  disease.  The  habitual  beer  drinker  is  less  able 
to  endure  an  attack  of  pneumonia,  typhoid  fever,  or  heart 
disease  than  the  total  abstainer. 

The  president  of  a  leading  life- 
insurance  company  once  said  of 
this  class  of  drinkers :  "  It  was  as 
if  the  system  had  been  kept  fair 
outside,  while  within  it  was  eaten 
to  a  shell,  and  at  the  first  touch  of 
disease  there  was  utter  collapse  : 
every  fiber  was  poisoned  and  weak. 
And  this,  in  its  main  features,  vary- 
ing of  course  in  degree,  has  been 
my  observation  of  beer  drinking  everywhere.  It  is  pecul- 
iarly deceptive  at  first,  and  it  is  thoroughly  destructive  at 
the  last." 

In  brief,  the  practical  experience  of  the  leading  life- 
insurance  companies  teaches  them  that  the  habitual  beer 
drinker  is  a  precarious  risk.1 

134.  Cider.  When  the  juice  is  first  pressed  from  apples 
everybody  knows  that  it  is  healthful  and  refreshing,  but 

1  This  flooding  the  stomach  and  brain  with  beer,  so  prevalent  among  our 
young  students ;  the  habit  of  drinking  between  meals,  especially  during  the 
forenoon  ;  this  daily  beer  drinking,  for  hours  at  a  stretch,  customary  among 
great  numbers  of  the  lower  and  middle  classes  in  Germany;  —  I  regard  it 
all  as  a  national  evil,  whether  considered  from  the  hygienic,  economic,  or 
intellectual  point  of  view.  —  PROFESSOR  BINZ,  of  the  University  of  Bonn, 
Germany. 


FIG.  62.  Yeast  Cells,  found 
in  the  Juice  of  Apples, 
which  cause  the  Fermen- 
tation of  Cider. 


92  OUR   BODIES   AND   HOW   WE    LIVE 

it  remains  so  for  a  few  hours  only.  The  ferments  which 
exist  in  the  air  and  on  the  skin  of  the  fruit  fall  into  the 
liquid  and  begin  to  play  their  part.  The  liquid,  or  cider, 
begins  to  "work,"  or  undergo  the  process  of  fermentation. 
As  it  was  with  grape  juice,  so  it  is  with  the  juice  of  the 
apple.  The  bubbles  of  carbon  dioxide  begin  to  rise  and 
alcohol  is  produced. 

The  amount  of  alcohol  increases  a  little  every  day,  so 
that  the  apple  juice,  which  was  harmless  while  in  the 
apple,  soon  becomes  a  source  of  danger.  In  a  few  weeks 
it  may  contain  almost  as  much  alcohol  as  we  find  in  beer. 

As  cider  grows  older  it  is  said  to  be  growing  hard  ;  that 
is,  the  amount  of  alcohol  in  it  is  increasing.  Hard  cider 
may  contain  ten  per  cent  of  alcohol. 

It  is  well  known  that  the  results  of  intoxication  from 
old  cider  are  as  bad  as,  if  not  worse  than,  those  resulting 
from  indulgence  in  ardent  spirits.  Many  a  person  has 
acquired  the  appetite  for  distilled  liquors  from  drinking 
hard  cider. 

135.  The  Process  of  Distillation.  We  all  know  that 
when  water  is  heated  to  the  boiling  point,  or  212°  F.,  it 
rapidly  changes  into  vapor,  known  as  steam.  How  often 
have  we  watched  the  steam  escaping  from  the  boiling  tea- 
kettle and  floating  away  as  vapor  to  cool  off  as  little  drops 
of  water  on  the  cold  window  glass  ! 

Now,  when  a  fermented  liquor  is  heated,  a  similar  change 
takes  place.  The  alcohol  does  not,  however,  need  to  be 
heated  nearly  so  hot  as  water  before  it  begins  to  escape  as 
vapor.  In  other  words,  the  alcohol  will  be  converted  into 
vapor  before  the  water  becomes  hot  enough  to  form  steam. 

Thus,  when  alcohol  and  water  are  mixed  together,  as  in 
fermented  liquors,  the  vaporized  alcohol  which  is  driven  off 


NATURE    OF   FERMENTED   DRINKS  93 

before  the  water  has  been  heated  enough  to  become  vapor, 
and  conducted  through  a  coil  of  pipes  kept  cool  by  running 
water,  is  changed  back  to  a  liquid  form  and  collected  in  a 
receiving  vessel. 

The  result  is  a  new  and  stronger  liquid,  known  as 
"spirits"  or  "ardent  (burning)  spirits,"  which  is  nearly  or 
more  than  half  alcohol.  This  new  liquid  is  whisky,  gin, 
or  brandy,  according  to  the  substance  or  flavors  used  in 
the  process  of  manufacture. 

This  process  of  separating  one  liquid  from  another  by 
vaporizing  with  heat  and  condensing  the  vapor  with  cold 
is  called  distillation. 

The  products  of  the  process  are  known  as  distilled 
liquors. 

136.  Distilled  Liquors.     Many  of  the  alcoholic  liquids 
are  made  by  distillation.     Thus,  alcohol  itself  may  be  dis- 
tilled several  times  until  we  get  a  much  stronger  liquid, 
clear  and  colorless  like  water,  with  a  sharp,  sweetish  taste 
and  a  peculiar  odor.     Various  kinds  of  alcohol  are  distilled 
from   wood,  from   wine  and  beer,  and  from   whisky  and 
fermenting  potatoes  and  tomatoes.     These  different  forms 
of  alcohol  vary  in  composition,  but  they  are  alike  in  one 
essential  property,  —  they  are  all  narcotic  poisons. 

The  more  common  distilled  liquors  used  as  beverages 
are  whisky,  brandy,  rum,  and  gin.  Rum  is  distilled  from 
the  fermented  molasses  of  sugar  cane  ;  brandy  from  wine  ; 
whisky  from  fermented  potatoes  and  corn ;  and  gin  from 
the  cereals  flavored  with  juniper  berries.  These  distilled 
liquors  contain  from  forty  to  fifty  per  cent  of  alcohol,  the 
rest  being  water  flavored  with  various  aromatics. 

137.  The  Action  of  Certain  Poisons.     A  poison  is  a  sub- 
stance whose  nature  it  is,  when  absorbed  into  the  blood, 


94  OUR  BODIES  AND   HOW   WE   LIVE 

either  to  destroy  life  or  impair  the  functions  of  one  or  more 
of  the  bodily  organs.  Again,  a  poison  which  especially 
affects  the  brain  centers,  producing  stupor,  is  called  a  nar- 
cotic poison.  Now,  as  we  shall  learn  later,  the  primary 
effect  of  alcohol  is  to  deaden  the  great  nerve  centers,  and 
hence  it  is  usually  classed  as  a  narcotic  poison. 

When  we  read  about  poisons  we  are  apt  to  think  only 
of  those  substances  that  may  cause  death  in  a  very  short 
time.  Among  them  are  laudanum,  strychnine,  and  car- 
bolic acid.  But  we  must  remember  that  there  are  many 
poisons  which  do  their  work  very  slowly.  Thus,  arsenic  in 
large  doses  may  destroy  life  in  a  few  moments  or  it  may  be 
taken  day  by  day  in  such  small  amounts  that  many  months 
or  even  years  may  elapse  before  death  results. 

Lead  used  by  painters  may  be  absorbed  so  slowly  that  it 
may  take  months  before  its  victims  learn  by  severe  cramps 
in  the  bowels  and  the  "wrist  drop"  that  the  poison  has 
been  slowly  accumulating  in  the  tissues  before  any  outward 
sign  of  its  action  was  evident. 

138.  Alcohol  a  Poison.  Alcoholic  liquors  may  be  taken 
in  such  quantities  at  a  single  dose,  either  by  accident  or 
design,  as  to  paralyze  the  great  nerve  centers  and  cause 
immediate  death.  Thus,  cases  are  on  record  in  which 
whisky  has  been  drunk  on  a  wager  and  gin  taken  in  igno- 
rance by  children  in  such  quantities  as  to  produce  deep 
stupor  and  death.  While  alcohol  may  thus  act  in  large 
quantities  as  a  quick  and  powerful  poison,  in  the  vast 
majority  of  cases  it  is,  of  course,  taken  in  comparatively 
smaller  amounts. 

Hence,  while  this  action  of  the  narcotic  is  slower,  it  is 
none  the  less  subtle  and  deadly  in  its  poisonous  effect 
upon  the  various  tissues  of  the  body. 


NATURE   OF    FERMENTED    DRINKS  95 

Alcohol  thus  answers  to  the  definition  of  a  poison  because 
it  has  an  inherent  harmful  property  which  on  becoming 
mixed  with  the  blood  is  capable  of  destroying  life,  as  would 
arsenic,  opium,  and  many  other  deadly  drugs. 

Remember,  then,  that  alcohol  is  a  poison  and  is  classed  as 
such  in  standard  medical  dictionaries  and  by  eminent  medi- 
cal authorities.1 

139.  Total  Abstinence  the  Only  Safeguard.  No  one  is  safe 
who  begins  to  take  any  liquor  containing  alcohol.  Entire 
abstinence  is  the  only  safeguard  against  forming  the  alco- 
holic appetite,  and  the  only  cure  for  it  when  it  is  formed. 

1  Alcohol  is  a  poison.  So  is  strychnine ;  so  is  arsenic ;  so  is  opium. 
It  ranks  with  these  agents.  —  SIR  ANDREW  CLARK,  M.D. 

Is  alcohol  a  poison  ?  I  reply,  Yes.  It  answers  to  the  description  of  a 
poison.  It  possesses  an  inherent,  deleterious  property,  which,  when  intro- 
duced into  the  system,  is  capable  of  destroying  life,  and  it  has  its  place  with 
arsenic,  belladonna,  prussic  acid,  opium,  etc.  In  its  effects  upon  the  living 
system  alcohol  is  first  an  irritant,  and  afterward,  when  it  has  entered  the 
circulation,  it  becomes  a  narcotic.  Were  alcohol  an  irritant  only,  a  man 
would  as  soon  poison  himself  with  arsenic.  The  narcotic  element  is  the 
siren  that  leads  him  on  to  ruin  and  to  death.  —  WILLARD  PARKER,  M.D. 

A  very  large  number  of  people  are  dying  day  by  day,  poisoned  by  alcohol, 
but  not  supposed  to  be  poisoned  by  it.—  SIR  WILLIAM  GULL,  M.D. 

Alcohol  is  a  virulent  poison,  and  as  such  should  be  placed  in  the  list  with 
arsenic,  mercury,  and  other  dangerous  drugs.  —  ALFRED  CARPENTER,  M.D., 
Examiner  of  Public  Health  in  the  University  of  London,  President  of  the 
Council  of  the  British  Medical  Association. 

Compared  with  the  small  quantity  of  adulterants  found  in  spirituous 
drinks,  ethyl  alcohol  is  so  significant  that  it  clearly  forms  the  chief  poison. 
—  PROFESSOR  J.  A.  SIKORSKY,  of  the  University  of  Kiev. 

Experiments  have  demonstrated  that  even  a  small  quantity  of  alcoholic 
liquor,  either  immediately  or  after  a  short  time,  prevents  perfect  mental 
action  and  interferes  with  the  functions  of  the  cells  and  tissues  of  the  body, 
impairing  self-control  by  producing  progressive  paralysis  of  the  judgment 
and  of  the  will ;  and  has  other  markedly  injurious  effects.  Hence  alcohol 
must  be  regarded  as  a  poison  and  ought  not  to  be  classed  among  foods. — 
An  International  Manifesto  against  the  Use  of  Alcoholic  Beverages,  signed  by 
over  eight  hundred  total  abstaining  practitioners  of  medicine  in  this  country 
and  Europe. 


96  OUR  BODIES  AND   HOW  WE   LIVE 

Because  of  the  ease  with  which  the  alcoholic  appetite  is 
roused  when  it  has  been  once  formed,  and  the  power  of 
a  very  small  amount  of  strong  drink  to  stimulate  such  an 
appetite,  there  may  be  a  real  danger  in  using  wine,  rum, 
and  brandy  as  a  flavoring  for  pies,  pudding  sauces,  jellies, 
or  any  other  article  of  food. 

140.  The  Danger  of  Social  Drinking.    The  habit  of  treat- 
ing one's  friends  to  beer,  wine,  or  any  other  alcoholic  drink 
is  simply  asking  them  to  injure  their  health  at  our  expense. 
Such  treating  is  a  mark  of  imprudence  rather  than  an  evi- 
dence of  real  courtesy  or  friendship,  and  it  must  be  so  con- 
sidered by  one  who  understands  the  true  nature  of  such 
substances. 

Furnishing  wines  or  liquors  at  parties,  dinners,  or  other 
entertainments,  or  for  guests  or  callers,  is  virtually  offering 
poisonous  drinks,  and  is  never  an  act  of  true  or  intelligent 
hospitality  or  real  kindness.  It  may  be  placing  temptation 
too  strong  to  be  resisted  in  the  way  of  an  inherited  or 
acquired  appetite  for  alcohol. 

The  eminent  Dr.  Horsley,  a  professor  in  University  Col- 
lege, London,  in  closing  a  lecture  recently  on  the  effects 
of  small  quantities  of  alcohol  on  the  brain,  said  :  "  The  con- 
tention so  often  made  that  small  doses  of  alcohol,  such  as 
people  take  at  meals,  have  practically  no  deleterious  effect 
cannot  be  maintained.  From  the  scientific  standpoint  total 
abstinence  must  be  the  course  if  we  are  to  follow  the  teach- 
ing of  truth  and  common  sense." 

141.  The  Alcohol  Habit.     Alcohol,  like  so  many  other 
narcotic  poisons,  has  the  peculiar  power  when  taken  fre- 
quently, even  in  small  quantities,   of  creating  a  diseased 
appetite  or  craving  for  itself,  which  calls  for  repeated  and 
increasing  amounts.     This  is  known  as  the  alcoholic  habit  or 


NATURE   OF   FERMENTED   DRINKS  97 

appetite.  All  natural  appetites  have  natural  limits.  But 
the  appetite  for  alcohol,  created  by  the  diseased  conditions 
which  it  has  itself  produced,  has  no  limit  to  its  baneful 
effects  upon  the  health. 

From  the  first  glass  of  beer  or  wine  sipped  by  the  boy 
who  is  just  beginning  to  drink  to  the  dram  of  the  drunkard 
whose  tissues  are  poisoned  by  it,  the  nature  of  alcohol  is 
to  excite  a  thirst  for  more.  Whether  it  is  used  in  the  form 
of  wine,  beer,  cider,  rum,  or  whisky,  its  character  is  the 
same ;  for  the  character  of  any  substance  depends  upon 
its  quality,  not  its  quantity. 

The  secret  of  the  drunkard's  craving  for  alcohol  is  in 
the  nature  of  the  drink  rather  than  in  the  weakness  of  the 
drinker. 

142.  The  Oxidation  of  Small  Quantities  of  Alcohol  in  the 
Body.     When  alcoholic    beverages  are  used  in  small  or 
moderate  quantities,  the  greater  part  of  their  alcohol  is 
burnt  up  or  oxidized  within  the  body.     The  alcohol  thus 
disposed  of  gives  out  a  certain  amount  of  energy,  as  truly 
as  the  oxidation  of  ordinary  food  materials   in  the  body 
yields  energy. 

We  must  remember,  however,  that  the  result  to  the  body 
is  quite  different  from  that  of  the  oxidation  of  food.  When 
foods  like  sugar  or  starch  are  used  as  sources  of  energy 
there  is  no  injurious  effect  upon  the  nervous  system ;  but 
the  use  of  enough  alcohol  to  supply  an  appreciable  amount 
of  energy  impairs  the  higher  functions  of  the  brain,  such 
as  the  ability  to  reason  accurately  or  to  exercise  complete 
self-control. 

143.  Alcohol    not    a    Food.     Definitions    of    the    word 
"food"  are  not  always  expressed  in  the  same  terms,  but 
the    following    essential   points    should  be   included  in  a 


98  OUR   BODIES   AND   HOW  WE   LIVE 

comprehensive  definition  :  A  food  is  a  substance  whose 
nature  it  is,  when  taken  into  the  system,  to  build  up  and 
repair  the  body  and  to  supply  it  with  energy  for  heat  and 
muscular  work  without  injury  to  any  of  its  tissues. 

Alcohol  in  small  quantities,  as  we  have  just  learned,  is 
oxidized  in  the  body,  and  its  energy  transformed  into  heat, 
as  truly  as  sugar,  starch,  or  fat.  It  by  no  means  follows, 
however,  that  alcohol  is  therefore  a  food  in  the  ordinary 
sense  in  which  the  term  "food"  is  used.  Many  harmful 
substances,  as  ether,  morphine,  and  other  powerful  drugs, 
are  oxidized  within  the  body  and  furnish  a  certain  amount 
of  energy,  and  yet  nobody  classes  these  as  foods.  While  it 
may  be  true  from  a  purely  scientific  and  technical  point  of 
view  that  alcohol  by  its  oxidation  may  set  free  a  certain 
amount  of  energy  within  the  body,  the  sum  total  of  its 
effects  is  injurious  rather  than  beneficial.  Hence  there 
is  clearly  no  good  reason  for  calling  alcohol  a  food  in  the 
ordinary  meaning  of  the  term. 

Standard  authorities,  moreover,  class  alcohol  as  a  power- 
ful drug,  —  a  narcotic  poison  rather  than  a  food.  When 
we  stop  to  think  of  the  possibilities  concerned  in  drinking 
even  a  very  small  quantity  of  alcoholic  liquor,  the  idea  of 
calling  it  a  food  is  an  evident  contradiction  of  terms.1 

1  Alcohol  does  not  act  as  a  food ;  it  cuts  short  the  life  of  rapidly  growing 
cells  or  causes  them  to  grow  more  slowly. —  LIONEL  S.  BEALE,  M.D.,  Pro- 
fessor of  Principles  and  Practice  of  Medicine,  King's  College,  England. 

I  find  alcohol  to  be  an  agent  that  gives  no  strength,  that  reduces  the 
tone  of  the  blood  vessels  and  heart,  that  reduces  the  nervous  power,  that 
builds  up  no  tissue,  and  can  be  of  no  use  to  me  or  any  other  animal  as  a 
substance  for  food.  —  SIR  HENRY  THOMPSON,  M.D. 

Certainly  alcohol  cannot  be  regarded  as  an  efficacious  food  for  muscles, 
nerve  cells,  and  the  like.  Not  even  in  a  narrow  sense  can  it  take  the  place 
of  a  force-generating  food  material.  —  ADOLF  FICK,  M.D.,  University  of 
Wurzburg,  Germany. 


NATURE    OF    FERMENTED    DRINKS  99 


QUESTIONS   ON  THE  TEXT 

I.  Of  what  are  fruit  juices  composed?     2.  What  happens  to  these 
fruit  juices  if  left  exposed  to  air  of  ordinary  temperature  ?     3.  What 
is    meant   by   nature's    great   law    of   decay?     Illustrate.     4.  What 
name   is   given    to    the    process    of    decay    that    goes    on    in    fruit 
juices  that  are  pressed  out  and  left  exposed  to  the  air?     5.  What 
does  fermentation  in  its  widest  sense  include?     6.  State  briefly  the 
law   of   fermentation.      7.  What    causes    the    various   processes   of 
decomposition?      8.  What  would  be  the  condition  of  the  earth  if  it 
were  not  for  these  minute  living  forms?     9.  To  what  is  the  general 
name  "bacteria"   applied?     10.  What  are  the  shape  and  size  of 
several  different  kinds  of  bacteria  ? 

II.  What  is  mold?      Illustrate.     12.  Mention  three  of  the  more 
common  forms  of  fermentation.     13.  Upon  what  is  alcoholic  fermen- 
tation in  general  based?    14.  What  change  in  fruit  juices  and  cereals 
is  brought  about  by  fermentation  ?     15.  Explain  in  full  how  wine  is 
produced  by  fermentation.    16.  What  is  the  great  danger  from  drink- 
ing wine  ?     17.  What  are  malt  liquors  ?     18.  Explain  how  alcohol  is 
formed  by  the  fermentation  of  cereals.     19.  What  can  you  say  of 
the  food  value  of  beer?      20.   Does   the  drinking  of  beer  tend  to 
diminish  the  use  of  ardent  spirits  ? 

21.  Describe  the  physiological  effect  of  drinking  malt  liquors. 
22.  What  is  the  testimony  of  life-insurance  companies  in  regard  to 
beer  drinking?  23.  Explain  how  cider  is  made  by  the  fermentation 
of  the  juice  of  apples.  24.  Explain  the  process  of  distillation. 
25.  From  what  are  the  various  distilled  liquors  made  ?  26.  What  is 
a  poison?  27.  What  is  a  narcotic  poison?  28.  Show  why  alcohol  is 
a  poison.  29.  What  is  the  only  safeguard  against  forming  the  alco- 
holic appetite  and  the  only  cure  when  it  is  formed  ?  30.  What  are 
some  of  the  dangers  of  social  drinking? 

31.  Explain  in  full  what  is  meant  by  the  alcohol  habit.  32.  How 
does  the  result  of  the  oxidation  of  alcohol  upon  the  body  differ  from 
that  of  the  oxidation  of  food  ?  33.  Give  the  essential  points  in  the 
definition  of  a  food.  34.  Explain  why  alcohol  is  not  a  food  in  the 
ordinary  meaning  of  the  word.  35.  How  is  alcohol  classed  by 
standard  authorities  ? 


CHAPTER  VI 
THE  DIGESTION  OF  FOOD 

144.  The  Object  of  Digestion.    The  tissues  of  the  body 
cannot  take  up  and  use  the  food  materials  in  the  form 
in  which  they  exist  in  the  food  we  eat.     They  must  first 
be  brought   into  a   condition   of    solution.      This   is   done 
that   they   may   be   absorbed   or   be   able  to  make  their 
way  through  the  tissues  forming  the  delicate  walls  of  the 
alimentary  canal. 

In  the  next  place,  the  food  materials  must  undergo  cer- 
tain chemical  changes  whereby  they  can  be  assimilated  or 
taken  up  by  the  tissues. 

This  most  wonderful  process  by  which  the  food  mate- 
rials are  made  capable  of  absorption  and  assimilation  is  known 
as  digestion. 

The  special  organs  concerned  in  bringing  about  this 
marvelous  change  in  the  food  are  the  digestive  organs. 

145.  The  Alimentary  Canal.     The  food  tube  from  the 
mouth  to  the  lowest  part  of  the  intestines  is  known  as  the 
alimentary  canal,  because  it  is  for  the  alimentation,  or  feeding, 
of  the  body. 

Beginning  at  the  mouth,  this  food  tube  continues  as  the 
gullet,  or  (Esophagus.  It  then  pierces  the  diaphragm,  which 
forms  the  partition  between  the  chest  and  the  abdomen 
(Figs.  83  and  103). 

Lower  down  the  food  tube  swells  out  into  a  large  bag 
called  the  stomach. 

100 


THE   DIGESTION   OF   FOOD 


101 


The  food  tube  then  narrows  again  into  the  small  intestine, 
which  is  coiled  upon  itself  in  the  abdomen.  It  now  expands 
again  into  the  large  intestine, 
from  which  are  discharged 
the  waste  materials. 

Layers  of  muscles  which 
help  to  push  along  the  food 
surround  this  long  food 
tube.  In  and  around  this 
tube  are  many  organs  called 
glands.1  They  pour  out 
certain  fluids,  which  moisten 
the  food,  change  it  chemi- 
cally, and  otherwise  make 
it  ready  to  be  taken  into 
the  blood. 

146.  The  Mouth.  The 
first  change  which  food 
undergoes  when  taken  into 
the  alimentary  canal  is  in 
the  mouth. 

In  the  mouth  the  food  is 
rolled  over  by  the  tongue, 
mixed  with  saliva,  and 


FIG.  63.     A  View  of  the  Back  Part 
of  the  Adult  Mouth. 


The  head  is  represented  as  having  been 
thrown  back,  and  the  tongue  drawn 
forward.  A,  £,  incisors;  C,  canine; 
D,  E,  bicuspids;  F,  H,  K,  molars; 
M,  anterior  pillar  of  the  fauces-;  N, 
tonsil ;  L,  uvula ;  O,  upper  part  of  the 
pharynx;  />,  tongue  drawn  forward; 
R,  linear  ridge,  or  raphe. 


1  Glands  are  curious  organs  of 
various  shapes  and  sizes,  whose 
special  work  it  is  to  take  out  of  the 
blood  something  to  be  used  again, 
or  to  rid  it  of  something  to  be  cast 
out  of  the  body.  Thus,  the  salivary 
glands  make  saliva,  or  spittle,  and 
the  sweat  glands  make  sweat.  The  liver,  which  weighs  from  three  to  four 
pounds,  is  a  single  gland,  and  secretes  bile  ;  while  the  glands  in  the  intestines 
are  so  very  small  that  they  cannot  be  seen  by  the  naked  eye  (Fig.  68). 


102  OUR   BODIES   AND    HOW   WE    LIVE 

crushed  and  ground  into  small  pieces  by  the  teeth. 
This  process  is  called  chewing  or  mastication. 

147.  The  Teeth.  The  teeth  serve  to  cut  and  grind  the 
food.  They  are  fastened  into  the  jaws  by  roots,  which 
sink  into  the  bony  sockets  somewhat  in  the  same  way  as 
a  nail  is  held  in  a  piece  of  wood. 

A  child  at  birth  has  no  teeth  ;  afterwards,  however,  two 
sets  are  developed,  one  after  the  other.  The  first  set,  or 


FIG.  64.     The  Temporary  and  Permanent  Teeth. 

Temporary  Teeth:  A,  central  incisors;  B,  lateral  incisors;  C,  canines;  D,  anterior 
molars ;  E,  posterior  molars.  Permanent  Teeth :  F,  central  incisors ;  H,  lateral 
incisors;  K,  canines;  Z,,  first  bicuspids ;  M,  second  bicuspids ;  N,  first  molars. 


temporary,  often  called  the  milk  teeth,  twenty  in  number, 
are  shed  in  childhood.  The  second  set,  or  permanent  teeth, 
thirty-two  in  number,  gradually  take  their  place. 

The  teeth  are  arranged  in  the  same  way,  and  number 
the  same  in  each  jaw  and  in  each  half  of  each  jaw. 


THE    DIGESTION    OF   FOOD 


I03 


:4r—  A 


148.  The  Structure  of  Teeth.     The  teeth  are  made  of 
three  materials,  —  dentine,  cement,  and  enamel.      Dentine,  the 
familiar  ivory  of  commerce,  is  a  bonelike  substance  which 
forms  the  inside  and  body  of  the  tooth. 

Outside  of  this  dentine  or  the  root  is 
a  layer  of  cement  ;  but,  when  the  tooth 
appears  above  the  jaw,  the  enamel  takes 
the  place  of  the  cement.  Enamel  is  a 
hard,  shining  material  which  looks  like 
ivory,  and  gives  a  strong  protection  to 
the  exposed  part  of  the  tooth,  called 
the  crown. 

Inside  of  each  tooth  is  a  space  which 
holds  a  delicate  substance  called  the 
pulp,  well  supplied  with  nerves  and 
blood  vessels  which  enter  at  the  root 
of  the  tooth. 

149.  The  Different  Kinds  of  Teeth. 
Beginning  at  the  center  of   the  jaw, 
there  are  eight  incisors,  or  cutting  teeth, 

two  on  each  side.  They  have  sharp,  FIG.  65.  BLACKBOARD 
chisel-like  edges,  which  cut  up  the  food.  SKETCH. 

These  teeth  are  largely  developed  in   Longitudinal  Section  of 
gnawing  animals,  such  as  rabbits,  squir- 
rels,  rats,  and  beavers. 

Then  come  the  canine,  or  dog  teeth, 

two  in  each  jaw,  so  called  because  they  are  strongly  devel- 
oped in  dogs,  cats,  tigers,  and  other  flesh-eating  animals. 
The  two  upper  canines  are  commonly  known  as  the  eye 
teeth,  and  the  two  lower  as  the  stomach  teeth. 

Next  come  the  bicuspids,  four  in  each  jaw.     They  have 
two  points,  or  cusps,  for  grinding  the  food. 


104 


OUR  BODIES  AND   HOW   WE    LIVE 


Next  in  order,  after  the  bicuspids,  come  the  largest  and 
strongest  teeth,  which  do  the  hardest  work.  They  are 
called  molars,  or  grinders.  There  are  six  of  them  in  each 
jaw.  They  have  broad  crowns,  with  four  or  five  cusps 
or  ridges  for  grinding.  The  last  molars  are  commonly 
called  the  "wisdom  teeth,"  because  they  do  not  usually 

appear  before  the  age 
of  twenty,  or  the  "  age 
of  wisdom"  (Sec.  178). 

Experiment  28.     Get  a 

specimen  of  each  kind  of 
tooth  if  possible.  A  den- 
tist friend  will  give  you 
what  you  need.  Use  a 
very  fine  saw  to  cut  a  per- 
fect molar  in  two  length- 
wise. If  need  be,  crack 
the  tooth  with  a  hammer. 

Note  its  structure  in  a 
general  way,  —  its  crown, 
cusps,  roots,  enamel,  den- 
tine, pulp  cavity,  etc. 

Make  a  blackboard 
sketch  of  a  tooth  on  a 
large  scale,  using  colored 
crayon  to  make  plain  the 
various  parts  (Fig.  65). 

Experiment  29.  With  the  help  of  a  mirror,  let  each  pupil  locate 
his  own  teeth.  Note  the  incisors,  eye  teeth,  bicuspids,  molars,  and 
wisdom  teeth,  if  any.  In  the  same  way,  note  the  teeth  of  some 
schoolmate. 

150.  The  Salivary  Glands.  While  the  food  is  being 
chewed  it  is  moistened  by  the  saliva,  or  spittle,  which  flows 
into  the  mouth  from  six  little  glands.  They  are  known  as 
the  salivary  glands.  There  are  three  of  them  on  each  side. 


SUBMAXILLARY 
CLANO 


FIG.  66.     BLACKBOARD  SKETCH. 
Salivary  Glands  of  the  Right  Side. 


THE    DIGESTION   OF   FOOD 


105 


FIG.  67.     The  Principal  Organs  of  the  Thorax  and  Abdomen. 
The  principal  muscles  are  seen  on  the  left,  and  superficial  veins  on  the  right. 


106  OUR   BODIES   AND    HOW  WE    LIVE 

The  parotid  gland  lies  below  and  in  front  of  each  ear.1 

The  submaxillary  gland  is  under  the  lower  jaw. 

The  sublingual  gland  is  found  under  the  tongue,  in  the 
floor  of  the  mouth. 

Each  salivary  gland  opens  into  the  mouth  by  a  little  duct. 
Each  has  a  certain  resemblance  to  a  bunch  of  grapes, 
with  a  tube  for  a  stalk. 

151.  The  Action  of  Saliva.  Saliva  flows  rapidly  into 
the  mouth  while  we  are  chewing  food.  About  two  pints 
of  saliva  are  secreted  in  the  course  of  a  day.  Sometimes 

ABC  D 


FIG.  68.     Diagram  of  the  Structure  of 
Secreting  Glands. 

A,  simple  tubular  gland;  B,  gland  with  mouth  shut  and  sac  formed;  C,  gland 
with  a  coiled  tube ;  £>,  plan  of  part  of  a  racemose  gland. 

these  glands  are  busily  at  work  even  before  we  actually 
taste  food.  The  saliva  will  flow  into  the  mouth  even  at 
the  sight,  smell,  or  thought  of  food.  This  is  commonly 
known  as  "  making  the  mouth  water." 

The  saliva  mixes  with  food  and  softens  it,  and  aids  in 
speech  by  keeping  the  mouth  moist.  It  also  acts  upon  the 
starchy  matters  in  food  through  its  ferment,  called  ptyalin, 
and  changes  them  into  a  form  of  sugar  known  as  maltose. 

Experiment  30.  To  make  the  saliva  flow.  Think  of  some  favorite 
article  of  food,  and  note  the  flow  of  saliva.  Push  a  lead  pencil  or  the 
finger  to  and  fro  in  the  mouth  several  times,  and  note  the  flow  of  saliva. 

1  This  gland,  especially  in  childhood,  sometimes  becomes  inflamed  and 
swollen  in  the  disease  familiarly  known  as  "  mumps." 


THE   DIGESTION    OF   FOOD 


107 


Experiment  31.  To  show  the  action  of  saliva  on  starch.  Chew 
slowly  a  piece  of  fresh  bread.1  Note  how  sweet  it  tastes  after  it 
is  well  wet  with  the  saliva.  Do  the  same  with  a  mouthful  of  paste 
made  of  pure  arrowroot  (almost  pure  starch)  and  boiling  water,  and 
allowed  to  cool. 

152.  What  is  meant  by  Secretion.  It  is  necessary  to  explain 
at  this  point  the  exact  meaning  of  secretion  and  excretion. 
The  word  "secre- 
tion "  comes  from  a 
Latin  word  which 
means  to  sift  or  sep- 
arate; excretion 
comes  from  the 
Latin,  and  means  to 
sift  out  from.  Both 
words  are  used  to 
express  the  sifting 
of  some  substance 
from  the  blood. 

A  secretion  is 
something  taken 
from  the  blood  to  be 
used  again  in  the 
body  for  some 
special  purpose  ; 
while  an  excretion  is 
waste  matter,  and  is 
thrown  out  of  the 
body  entirely.  Thus, 
the  salivary  glands 
secrete  the  saliva, 


FIG.  69.  Cavities  of  the  Mouth,  Pharynx,  etc. 
Section  in  the  middle  line  designed  to  show  the  mouth 
in  its  relations  to  the  nasal  fossae,  the  pharynx,  and 
the  larynx.  A,  sphenoidal  sinus;  B,  internal  orifice 
of  Eustachian  tube ;  C,  velum  palati ;  £>,  anterior 
pillar  of  soft  palate ;  E,  posterior  pillar- of  soft  palate ; 
F,  tonsil ;  ff,  lingual  portion  of  the  pharynx ;  K,  lower 
portion  of  the  pharynx ;  L,  larynx ;  Af,  section  of 
hyoid  bone  ;  IV,  epiglottis  ;  O,  palatine  arch. 


1  Chew  pieces  of  the  brown  crust  of  the  bread.  It  is  quite  sweet  and 
readily  dissolves,  because,  exposed  to  more  heat  than  the  rest  of  the  loaf, 
the  starch  has  been  changed  into  dextrin  before  the  bread  left  the  oven. 
Hence  crust  and  toast  are  favorite  articles  of  food,  especially  with  old 
people. 


108  OUR  BODIES  AND   HOW  WE   LIVE 

and  the  liver  secretes  the  bile.     Sweat  is  an  excretion  thrown 
off  from  the  body  by  the  sweat  glands. 
Excretion  will  be  described  in  Chapter  IX. 

153.  How  Food  is  swallowed.  The  food  is  now  ready  to 
be  swallowed.  The  soft,  moist  mass  is  carried  backwards 
by  the  tongue  and  the  muscles  of  the  mouth  into  the 
funnel-shaped  part  above  the  gullet,  called  the  pharynx. 
The  soft  palate  moves  upwards  and  backwards,  so  as  to 
prevent  the  food  from  passing  into  the  nose1  (Fig.  69). 

Now,  besides  the  opening  from  the  pharynx  into  the 
gullet,  there  is  also  one  into  the  windpipe.  To  prevent 
the  food  from  getting  into  this  opening  and  choking  us, 
the  top  of  the  windpipe  is  protected  by  a  little  lid,  a  kind 
of  trapdoor,  called  the  epiglottis  (Figs.  101  and  174). 

When  we  swallow,  the  tongue,  raised  and  pushed  back- 
wards, shuts  this  little  lid ;  and  thus  a  bridge  is  made,  over 
which  the  food  passes  downwards  into  and  through  the 
gullet,  and  thence  into  the  stomach. 

Sometimes,  however,  a  morsel  of  food  "goes  the  wrong 
way,"  —  that  is,  is  drawn  into  the  opening  of  the  windpipe, 
or  down  into  the  air  tubes,  —  and  then  violent  coughing 
follows  :  by  this  means  it  may  be  brought  up  again.  If  the 
substance  is  hard  and  large,  like  a  boot  button,  an  orange 
seed,  or  a  peanut,  a  person,  especially  a  child,  may  be  choked 
to  death. 

Experiment  32.  Open  the  mouth  wide ;  press  down  the  back  of 
the  tongue  gently  with  the  handle  of  a  teaspoon.  With  the  aid  of 
strong  sunlight  and  a  hand  mirror  the  epiglottis  may  be  seen. 

1  After  an  attack  of  diphtheria  the  parts  of  the  throat  are  sometimes 
partially  paralyzed.  The  soft  palate  is  not  able  to  shut  off  this  passage  into 
the  nose;  as  a  result,  milk  and  other  food  often  come  up  through  the  nose. 


THE   DIGESTION   OF   FOOD 


109 


154.  The  Gullet.  The  gullet,  or  food  pipe,  is  a  tube  about 
nine  inches  long,  hanging  loosely  behind  the  windpipe.  Its 
thick  walls  are  provided  with  hooplike  muscles  which  con- 
tract with  a  wavelike  motion,  well  seen  when  a  horse  is 

B  A 


FIG.  70.     BLACKBOARD  SKETCH. 

The  Stomach. 
A,  cardiac  end ;  B,  pyloric  end. 

drinking  water,  and  so  push  the  food  along  towards  the 
stomach.  The  pellet  of  food  is  pushed  downwards  by 
these  muscles1  in  some  such  way  as  we  would  push  any 
substance  along  inside  of  a  rubber  tube  (Fig.  83). 

Experiment  33.  Place  the  fingers  on  the  "Adam's  apple"  (Sec. 
379).  Pretend  to  swallow  something,  and  you  can  feel  the  upper 
part  of  the  windpipe  and  get  a  very  fair  idea  of  the  action  of  the 
epiglottis  and  the  closing  of  its  lid,  thus  covering  the  entrance  and 
preventing  the  passage  of  food  into  the  windpipe. 

1  It  is  important  to  remember  that,  in  swallowing,  the  food  and  drink 
do  not  simply  fall  down  the  gullet.  Their  passage  is  controlled  by  the 
muscles  in  such  a  way  that  they  grip  successive  portions  swallowed,  and 


no 


OUR   BODIES   AND    HOW   WE   LIVE 


155.  The  Stomach.  The  food,  a  moistened,  partly 
digested  mass,  has  now  reached  the  stomach,  which  is  a 
pear-shaped  bag,  or  pouch,  capable  of  holding  about  four 
pints.  It  lies  under  the  diaphragm,  chiefly  on  the  left 
side  of  the  abdomen. 

The  stomach  has  two  openings.     The  opening,  or  ring, 
through  which  the  food  enters,  is  called  the  cardiac  orifice. 
The  opening  at  the  right  end,  where 
the  intestines  begin  and  by  which  food 
leaves    the  stomach,   is  known  as  the 
pyloric  orifice.     It  is  guarded  by  a  kind 
of  valve  called  the  pylorus,  or  gate  keeper. 
156.  The  Coats  of  the  Stomach.    The 
outer  coat  of  the  stomach  is  the  smooth, 
glistening  serous  membrane  which  lines 
the  abdomen,  —  \\\t  peritoneum. 

The  inner  lining,  or  mucous  mem- 
brane, of  the  stomach  is  loose  and  wrin- 
kled when  the  stomach  is  empty,  and 
smoothed  out  when  it  is  full  of  food. 
Between  the  outer  smooth  coat  and  the 
inner  lining  lies  the  muscular  coat. 

The  inner  coat  of  the  stomach  has  its  surface  honey- 
combed with  millions  of  little  pits.  We  have  all  seen  this 
in  tripe.  In  the  floor  of  each  of  these  tiny  pits  a  number 
of  tubes  open.  These  are  the  openings  of  the  gastric 
glands. 

pass  them  along.  In  swallowing  a  pill  there  is  the  same  process.  The 
smaller  the  pill,  the  greater  the  difficulty  oftentimes  in  swallowing,  because 
the  muscles  have  more  trouble  in  getting  the  necessary  grasp  on  it.  Some  of 
us  have  seen  an  acrobat  or  juggler  stand  on  his  head,  and  drink  a  glass  of 
water,  and  even  eat  in  this  position.  We  may  see  the  same  thing  when  we 
watch  a  horse  or  a  cow  drinking  from  a  pail  of  water  on  the  ground. 


FIG.  71.     A  Gastric 
Gland. 


THE   DIGESTION    OF   FOOD 


III 


157.  Digestion  in  the  Stomach.     The  moment  the  food 
reaches  the  stomach,  the  muscles  begin  to  contract,  and  a 
spiral  wave  of    motion  begins,   becoming    more    rapid  as 
digestion  goes  on.     The  food  is 

rolled  over  and  over,  and  thor- 
oughly mixed  with  the  gastric 
juice.  Two  rings,  one  at  the 
entrance  and  the  other  at  the  out- 
let, keep  the  food  in  the  stomach 
while  it  is  being  churned  about 
and  digested. 

158.  The  Gastric  Juice.    Soon 
after  food  enters  the  stomach, 
drops    of    fluid    collect    at    the 
mouths    of    the    gastric   glands 
and   trickle   down   its  walls    to 
mix  with  the  food.    This  fluid  is 
known  as  the  gastric  juice. 

The  gastric  juice  is  a  clear,  almost  colorless  fluid,  with  a 
sour  taste  and  odor.  It  contains  a  peculiar  substance  called 
pepsin,  and  an  acid,  both  of  which  are  necessary  to  the 
digestion  of  food  in  the  stomach.  The  amount  of  gastric 
juice  has  been  variously  estimated,  — all  the  way  from  five 
to  fourteen  pounds  daily. 

Experiment  34.  To  show  how  the  wall  of  the  stomach  looks. 
The  wall  of  the  pig's  stomach  resembles^  that  of  the  human  stomach. 
Get  from  the  market  a  piece  of  a  pig's  stomach.  Cut  off  bits  of  it 
and  examine  it  thoroughly  with  a  hand  lens.  Scrape  off  the  inner, 
or  mucous,  coat  with  the  edge  of  a  very  sharp  knife.  Find  the 
openings  of  the  gastric  tubes  with  the  help  of  a  magnifying  glass. 
Pick  with  fine  needles  until  the  fibers  of  the  muscular  coat  are 
found.  Contrast  the  appearance  of  the  pig's  stomach  with  that  of 
a  cow  by  examining  a  piece  of  tripe. 


FIG.  72.  The  Inner  Surface 
of  the  Stomach,  from  which 
the  Epithelium  has  been  re- 
moved, showing  the  Open- 
ings of  Gastric  Glands. 
Magnified  20  diameters. 


112  OUR   BODIES    AND    HOW  WE   LIVE 

159.  The  Action  of  the  Gastric  Juice.     The  gastric  juice 
consists  of  water  with  a  little  hydrochloric  acid  and  two 
ferments  called  pepsin  and  rennin.     The  pepsin,  acting  in 
the  presence  of  a  weak  acid,  turns  the  proteid  food  stuffs 
into  what  are  called  peptones,  which  are  soluble  and  capa- 
ble of  being  absorbed  into  the  blood. 

The  gastric  juice  has  no  action  on  starchy  foods,  neither 
does  it  act  on  fats,  except  to  set  free  the  fat  from  the 
connective  tissue  which  contains  it. 

Experiment  35.  To  show  the  action  of  gastric  juice  on  milk.  Mix 
two  teaspoonfuls  of  fresh  milk  in  a  test  tube  with  a  few  drops  of 
artificial  gastric  juice,1  and  keep  at  about  100°  F.  In  a  short  time 
the  milk  curdles  so  that  the  tube  can  be  inverted  without  the  curd 
falling  out.  By  and  by  whey  is  squeezed  out  of  the  clot. 

160.  Passage  of  the  Food  into  the  Intestines.     After  two 
or  three  hours  of  digestion,  the  food  in  the  stomach  is 
reduced  to  a  pulpy  and  almost  fluid  condition.     It  now 
takes  on  the  appearance  of  pea  soup,  usually  of  a  grayish 
color,  and  is  called  chyme. 

After  one  to  four  hours,  the  chyme  begins  to  move  on 
in  successive  portions  into  the  first  part  of  the  small  intes- 
tine. The  ringlike  muscles  of  the  pylorus  relax  at  inter- 
vals to  allow  the  muscles  of  the  stomach  to  force  the  partly 
digested  mass  into  the  intestines. 

This  action  is  often  repeated  until  even  the  indigest- 
ible masses  which  the  gastric  juice  cannot  break  down  are 
crowded  out  of  the  stomach  into  the  intestines.  From  three 
to  four  hours  after  a  meal  the  stomach  is  quite  emptied. 

1  An  artificial  gastric  juice  may  be  obtained  for  experimental  purposes 
by  dissolving  about  ten  grains  of  pepsin  powder  (made  by  some  reputable 
manufacturer  and  obtained  of  any  druggist)  in  half  a  pint  of  water  and 
adding  perhaps  from  fifteen  to  twenty  drops  of  strong  hydrochloric  acid,  or 
about  six  times  as  much  of  the  dilute  acid. 


THE   DIGESTION   OF   FOOD  113 

Some  of  the  food,  while  in  the  stomach,  is  absorbed  into 
the  blood  current.      The  peptones  and  some  sugar  pass 


DIAPHRAGM 


FIG.  73.     Showing  the  Relations  of  the  Stomach,  Liver,  Intestines, 
Spleen,  and  other  Organs  of  the  Abdomen.     (Front  view.) 

A,  duodenum ;  B,  upper  end  of  the  small  intestine ;  C,  lower  end  of  the  small 
intestine ;  Z>,  caecum ;  £,  bladder.  The  liver  and  stomach  are  drawn  up, 
and  portions  of  the  small  intestine  have  been  cut  away. 

through  the  lining  membrane  into  the  capillaries  which  form 
a  close  network  in  the  mucous  membrane. 


114  OUR   BODIES   AMD   HOW  WE   LIVE 

161.  The  Small   Intestine.     The  intestines  consist  of  a 
long  tube  which  fills  the  greater  part  of  the  abdomen.    They 
are  divided  into  the  small  intestine,  about  twenty-five  feet 
long,  and  the  large  intestine,  about  five  feet  in  length. 

The  first  portion  of  the  small  intestine,1  which  is  directly 
continued  from  the  stomach,  is  called  the  duodenum,  because 
it  is  about  twelve  fingers'  breadth  long,  —  that  is,  about 
eight  inches. 

Let  us  now  see  what  takes  place  in  the  duodenum.  Two 
tubes,  or  ducts,  unite  and  enter  it.  One  comes  from  the 
liver  and  the  gall  bladder,  and  brings  the  bile;  the  other 
from  the  pancreas,  and  brings  the  pancreatic  juice.  These 
two  tubes  unite,  and  enter  the  duodenum  at  the  same 
place. 

162.  The  Liver  and  the  Work  it  jdoes.     The  liver  is  a  large 
reddish-brown  organ  situated  just  under  the  diaphragm,  and 
on  the  right  side.     It  is  the  largest  gland  in  the  body,  and 
weighs  about  three  and  one-half  pounds.     The  liver  secretes 
in  the  course  of  a  day  about  two  pints  of  an  important  fluid 
called  the  bile.     Some  of  it  is  stored  up  in  a  kind  of  little 
pear-shaped  bag  attached  to  the  liver  itself,  and  called  the 
gall  bladder. 

The  liver  also  makes  a  material  which  resembles  starch, 
called  glycogen,  or/  liver  sugar.  This  is  stored  in  the  liver 
when  food  is  plentiful,  and  is  used  up  during  starvation  or 
during  muscular  work. 

163.  The  Bile  and  how  it  helps  in  Digestion.     The  bile 
is  a  greenish-yellow,  bitter  fluid,  but,  when  acted  upon  by 
the  gastric  juice,  it  takes  on  a  distinctly  yellow  or  greenish 
hue  ;  hence  the  appearance  of  vomited  bile. 

1  The  small  intestine  includes  three  parts,  —  duodenum,  jejunum,  and 
ileum.  The  large  intestine  includes  the  caecum,  colon,  and  rectum  (Fig.  73). 


THE   DIGESTION    OF   FOOD  115 

The  chief  use  of  the  bile  is  to  help  digest  the  fatty  foods 
upon  which  the  gastric  juice  does  not  act.     The  bile  also 


FIG.  74.     The  Liver  seen  from  Below  and  Behind. 

A  and  B,  smaller  lobes  of  the  liver ;  C,  portal  vein  ;  D,  hepatic  artery ;  E,  inferior 
vena  cava ;  F,  trunk  of  left  hepatic  vein  ;  G,  hepatic  vein. 

contains  materials  separated  from  the  blood  which  are  of  no 
further  use  to  the  body  and  which  must  be  cast  out  before 
they  do  mischief. 

Experiment  36.  To  show  the  action  of  bile  on  fats.  Mix  three 
teaspoonfuls  of  bile1  with  a  half  teaspoonful  of  sweet  oil.  Shake 
well,  and  keep  the  tube  in  a  water  bath  at  about  100°  F.  A  very 
good  emulsion  is  obtained. 

1  Obtain  from  the  butcher  some  ox  bile.  Note  its  bitter  taste,  peculiar 
odor,  and  greenish  color.  It  is  alkaline  or  neutral  to  litmus  paper.  Pour 
it  from  one  vessel  to  another,  and  note  that  strings  of  mucus  (from  the 
lining  membrane  of  the  gall  bladder)  connect  one  vessel  with  the  other.  It 
is  best  to  precipitate  the  mucus  by  acetic  acid  before  making  experiments, 
and  to  dilute  the  clear  liquid  with  a  little  distilled  water. 


Il6  OUR  BODIES  AND   HOW  WE   LIVE 

164.  The  Pancreatic  Juice  and  what  it  does.  The  pan- 
creatic juice  is  secreted  by  a  long,  narrow,  flattened  gland  called 
the  pancreas,  or  sweetbread.  It  lies  behind  the  stomach  and 
is  often  said  to  resemble  a  dog's  tongue  (Fig.  73). 

The  pancreatic  juice,  by  means  of 
its  three  ferments,  finishes  the  work 
which  the  saliva  began.  It  acts 
chiefly  upon  the  starchy  foods  which 
have  escaped  the  action  of  the  saliva, 

""•  ^    *    e 

***  •-          and  changes  them  into  sugar.     It  also 

'.-'»  •  *  •  ; 

'"•' J'*-»'          follows  up  the  work  of  the  gastric 
: *."•;*••  •*•**.          juice,  and  acts  upon  the  proteids 

FIG.  75.  Vertical  Section  which  have  not  been  digested  in  the 
of  intestinal  Vim ;  Cross-  stomach,  changing  them  into  peptones. 
Section  below,  with  The  pancreatic  juice  acts  upon  the 

Black  Dots  representing  c 

Glandular  Openings.     '      dr°Ps  of  fat  m  such  a  wav  as  to  sP]lt 

them  into  glycerin  and  a  fatty  acid. 

The  latter  now  unites  with  the  alkali  of  the  pancreatic  juice 
and  the  bile,  and  forms  soap.  It  also  makes  what  is  called 
an  emulsion  out  of  the  fats ;  that  is  to  say,  it  breaks  them 
up  into  tiny  particles  and  they  become  white  like  milk. 

Experiment  37.  To  show  the  action  of  pancreatic  juice  on  the 
albuminous  ingredients  (caseiti)  of  milk.  Into  a  half-pint  bottle  (an 
infant's  nursing  bottle  will  answer  and  is  easily  obtained)  put  two 
tablespoonfuls  of  cold  water;  add  one  grain  of  pancreatin,  and  as 
much  baking  soda  as  can  be  taken  up  on  the  point  of  a  penknife. 
Shake  well,  and  add  four  tablespoonfuls  of  cold,  fresh  milk.  Shake 
again.  Now  set  the  bottle  into  a  basin  of  hot  water  (as  hot  as  one 
can  bear  the  hand  in),  and  let  it  stand  for  about  forty-five  minutes. 

Take  a  small  quantity  of  milk  in  a  test  tube,  and  stir  in  a  few  drops 
of  vinegar.  A  thick  curd  of  casein  will  be  seen.  Upon  applying  the 
same  test  to  the  digested  milk,  no  curd  will  be  made.  The  pancreatic 
ferment  (trypsin)  has  digested  the  casein  into  peptone,  which  does 
not  curdle. 


THE   DIGESTION   OF   FOOD 


117 


165.  How  Food  is  absorbed.     The  souplike  mass  which 
left  the  stomach  under  the  name  of  chyme  has  now  been 
changed  into  a  thick  cream  called  chyle.     Squeezed  slowly 
along  the  intestines  by  the  wavelike  motions  of  the  mus- 
cular walls,  the  food  materials  that  have  been  digested  and 
turned  into  a  soluble  form  are  absorbed.     In  other  words, 
they  pass  from  the  inside  of  the  intestines  into  the  blood 
vessels  and  the  lacteals  lying 

in  the  intestinal  walls. 

The  process  by  which  the  di- 
gested materials  are  taken  into 
the  blood  is  called  absorption. 
It  is  by  no  means  a  process 
that  is  confined  to  the  alimen- 
tary canal,  but  one  that  is  going 
on  in  every  tissue  of  the  body. 

This  is  done  chiefly  by  two 

sets   of   vessels,  —  first,  by  the     FIG.  76.    Glands  and  Villi  of  the 
lacteals,  or  lymphatics ;    second, 
by  the  blood  vessels. 

166.  The  Work  done  by  the 
Lacteals.      The  inner  surface 
of   the   small  intestine  is  not 

smooth  and  shiny,  like  the  outside,  but  has  a  velvety 
appearance.  This  is  because  it  is  crowded  with  millions 
of  little  club-shaped  threads  which  project  into  the  cavity 
of  the  intestine. 

These  projections  are  called  villi,  meaning  tufts  of  hair. 
They  are  tiny  threads,  about  one  thirtieth  of  an  inch  long ; 
and  a  five-cent  piece  would  cover  five  hundred  of  them. 
They  are  set  side  by  side  not  unlike  the  pile  on  velvet. 
These  villi  are  not  found  in  the  large  intestine. 


Small  Intestine. 
Magnified  40  diameters. 

A,  B,  glands  seen  in  vertical  section 
with  their  orifices  at  C  opening 
upon  the  membrane  between  the 
villi ;  D,  villus. 


n8 


OUR  BODIES   AND   HOW  WE    LIVE 


In  each  one  of  these  villi  is  a  network  of  the  finest  blood 
vessels,  and  a  tube,  or  canal,  called  a  lacteal,  so  called  from 
a  Latin  word  meaning  milky,  because  it  carries  a  white, 
milky  fluid.  Millions  of  these  lacteals  dip  down  into  the 
small  intestine,  like  little  root  fibers,  and  suck  up  the  drop- 
lets of  fat  or  the  glycerin  and  soaps  made  from  them. 

The  lacteals,  after  passing  through  a  number  of  glands 
—  like  way  stations  on  a  railroad  —  in  the  abdomen,  unite 


FIG.  77.     BLACKBOARD  SKETCH. 
Diagram  of  Intestinal  Absorption. 

A,  a  fold  of  peritoneum ;  B,  lacteals  and  lymphatic  glands ;  C<,  veins  of 
intestines;  R.C.,  receptacle  of  the  chyle  (receptaculum  chyli) ;  P.V., 
portal  vein;  H.V.,  hepatic  veins;  S.V.C.,  superior  vena  cava;  R.A., 
right  auricle  of  the  heart ;  7.F.C.,  inferior  vena  cava. 

into  larger  tubes,  and  finally  open  into  the  saclike  expan- 
sion of  the  lower  end  of  the  thoracic  duct,  known  as  the 
receptaculum  chyli.  Into  this  are  poured  not  only  the  con- 
tents of  the  lacteals  but  also  of  the  lymphatic  vessels  of 
the  lower  limbs  (Fig.  128). 

167.  The  Thoracic  Duct.  Sooner  or  later  most  of  the 
small  lymphatics  pour  their  contents  into  the  thoracic  duct. 
This  is  a  tube  about  as  large  as  a  goose  quill,  which  lies  in 
front  of  the  backbone.  It  serves  to  carry  the  nutritive 


THE   DIGESTION    OF   FOOD 


material  obtained 
from  the  food  and 
pours  it  into  the  blood 
current  at  the  junc- 
tion of  the  great  veins 
on  the  left  side  of  the 
head  with  those  of  the 
left  arm  (Fig.  103). 

The  remaining 
lymphatics,  chiefly 
those  on  the  right 
side,  are  connected 
with  the  great  veins 
of  the  right  side. 

168.  The  Work 
done  by  the  Lymphat- 
ics. In  nearly  every 
tissue  of  the  body 
there  is  a  marvelous 
network  of  vessels, 
precisely  like  the  lac- 
teals,  known  as  the 
lymphatics.  They  seem 
to  start  out  of  the  part 
in  which  they  are 
found,  like  the  root- 
lets of  a  plant  in  the 
soil.  The  tiny  roots 
join  together  and 
make  larger  roots. 
They  carry  a  fluid 
called  lymph,  very 


FIG.  78.     BLACKBOARD  SKETCH. 
Diagram  of  a  Transverse  Section  of  the 

Small  Intestine. 

In  the  figure  on  the  left  are  seen  the  artery  and  vein 
of  a  villus.  In  the  right  figure  are  represented 
the  central  lacteal  of  villus,  with  plexus  of  lymph 
vessels  at  the  base.  The  mucous,  submucous, 
muscular,  and  serous  coats  are  indicated  at  the 
base  of  the  right-hand  figure.  The  epithelium  of 
each  villus  is  well  shown. 


120  OUR   BODIES   AND   HOW  WE   LIVE 

much  like  blood  without  the  red  corpuscles.  It  is  to  be 
remembered  that  the  lacteals  are  really  the  lymphatics 
which  begin  in  the  villi  of  the  small  intestine. 

The  lymphatics  have  little  round  bodies,  about  the  size 
of  hazelnuts,  at  many  points  of  their  course,  scattered  like 
stations  along  a  line  of  railroad,  which  bodies  are  called 
lymphatic  glands.  They  seem  to  be  a  kind  of  magical  work- 
shops to  make  over  the  lymph  in  some  way,  and  to  fit  it 
for  being  poured  into  the  blood  (Figs.  80  and  81). 

Nature,  like  a  careful  housekeeper,  allows  nothing  to  go 
to  waste  that  can  be  of  any  service  to  the  body. 

169.  The  Spleen  and  Other  Ductless  Glands.     There  are  in 
the  body  a  number  of  organs  called  "  ductless  glands,"  because 
they  have  no  ducts  or  canals  along  which  may  be  carried  the 
products  of  their  work.     Their  products  are  carried  off  by  the 
blood  which  flows  through  them. 

The  'spleen  is  situated  in  the  abdomen  on  the  left  side,  and 
just  behind  the  stomach.  It  is  about  five  inches  long,  of  a 
deep  red  color,  and  full  of  blood  (Figs.  73  and  128). 

The  spleen  appears  to  take  some  part  in  the  formation  of 
blood  corpuscles.  In  certain  diseases,  like  malarial  fever,  it 
may  become  remarkably  enlarged. 

The  thyroid  gland  is  situated  beneath  the  muscles  of  the 
neck,  on  each  side  of  the  windpipe.  It  is  greatly  enlarged  in 
the  disease  called  goitre. 

The  thymus  gland  is  situated  around  the  windpipe,  behind 
the  upper  part  of  the  breast  bone.  Its  use  is  not  certainly 
known.  It  exists  only  during  early  life. 

The  suprarenal  capsules  are  two  little  glands,  one  perched 
on  the  upper  edge  of  each  kidney,  shaped  something  like  a 
cocked  hat.  Nothing  definite  is  known  about  them  (Fig.  128). 

170.  Absorption  by  the  Blood  Vessels.     We  have   just 
learned  that  the  fats  for  the  most  part  get  into  the  blood 


THE   DIGESTION    OF   FOOD 


121 


current  by  a  roundabout  way,  —  that  is,  into  the  lacteals, 
and  thence  into  the  other  lymphatics  and  the  thoracic  duct. 

The  peptones  and  sugar  are  also  carried  into  the  main 
blood  current  in  a  roundabout  way.     They  are  taken  up 
by  the  tiny  blood  vessels 
of  the  villi  and  then  car- 
ried along  the  portal  vein 
to  the  liver,  and  are  there 
acted    upon    before    they 
reach   the   general   blood 
stream.     (See  Portal  Cir- 
ctilation.  Sec.  210.) 

171.  The  Large  Intes- 
tine. The  large  intestine, 
which  is  about  five  feet 
long,  first  passes  up  the 
right  side  of  the  abdomen, 
then  across  under  the  liver 
and  stomach,  and,  lastly, 
descends  on  the  left  side 
of  the  abdomen.  It  then 
bends  sharply  and  ends  in 
the  rectum  in  the  middle 
line  of  the  body  (Fig.  73). 

Most  of  the  food  material  which  is  of  any  use  to  the  body 
has  been  absorbed  in  the  small  intestine.  The  large  intes- 
tine absorbs  a  good  deal  of  the  remainder,  especially  water. 

This  part  of  the  digestive  canal  also  serves  as  a  kind  of 
temporary  storehouse  for  indigestible  or  waste  materials 
which  are  to  be  cast  out  of  the  body.1 


FIG.  79.     The  Vermiform  Appendix. 

A,  a  portion  of -the  colon  laid  open  to  show 
the  valve  between  the  large  and  small 
intestine;  B,  the  caecum. 


1  The  vermiform  appendix,  inflammation  of  which  is  known  as  appendi- 
citist  is  a  curious  offshoot  from  the  large  intestine  near  the  point  where  it 


122  OUR   BODIES  AND   HOW  WE   LIVE 

172.  How  much  to  eat.     The  quantity  of  food  which  is 
needed   to  keep   the  body  in  good  health  varies  greatly 
according  to  circumstances.     The  greater  the  amount  of 
exercise,  the  more  food  is  called  for  to  supply  the  waste. 

During  the  time  of  growth,  a  still  greater  quantity  is 
needed  to  build  up  new  tissues  ;  hence  growing  children 
generally  have  a  good  appetite  and  a  vigorous  digestion. 
This  is  often  true  of  persons  who  are  recovering  from 
some  long  and  wasting  sickness. 

The  quantity  of  food  also  depends  very  much  upon  one's 
business.  Those  who  work  hard  and  long  need  a  goodly 
amount  of  nutritious  food.  Those  who  work  indoors  can 
get  along  with  a  smaller  quantity.  In  cold  weather,  or  in 
cold  climates,  a  greater  quantity  of  food  is  necessary  than 
in  warm  weather  or  in  a  tropical  climate. 

173.  The  111  Effects  of  eating  too  much.     An  appetite 
for  plain,  simple,  well-cooked  food  is  a  safe  guide  to  follow. 
Every  person  in  good  health  and  with  moderate  exercise 
should  have  a  keen  appetite  for  his  food,  and  enjoy  it. 

Young,  growing,  and  vigorous  persons  should  eat  plain 
food  until  the  appetite  is  fully  satisfied,  provided  they  have 
enough  exercise,  both  mental  and  bodily. 

It  is  easy  to  know  when  we  are  eating  too  much.  An 
overworked  stomach  makes  its  condition  known  by  a  sense 
of  fullness,  uneasiness,  drowsiness  after  meals,  and  some- 
times a  real  distress. 

is  joined  by  the  small  intestine.  It  is  a  hollow  tube  about  three  or  four 
inches  long,  and  about  the  thickness  of  a  lead  pencil.  From  a  surgical 
point  of  view,  it  is  of  great  importance  because  it  is  subject  to  sudden 
inflammation.  In  many  cases  an  operation  is  necessary  for  the  relief  of  the 
patient.  The  great  English  surgeon,  Treves,  operated  one  thousand  times 
for  appendicitis  without  the  loss  of  a  single  patient.  The  use  of  antiseptics 
in  recent  surgery  has  made  such  brilliant  results  possible  (Fig.  79). 


THE    DIGESTION    OF   FOOD  123 

If  we  are  in  the  habit  of  eating  too  much  and  too  rich 
food,  the  complexion  is  apt  to  be  muddy,  the  face  is  more 
or  less  covered  with  blotches  and  pimples,  the  breath  has 
an  unpleasant  odor,  and  the  general  appearance  is  dull  and 
unhealthy. 

174.  What  to  eat.  We  can  safely  eat  some  animal  food 
every  day,  yet  it  is  well  to  remember  that  the  vegetable 


FIG.  80.     Superficial  Lymphatics  of  the  Foot. 

albumins  supply  all  that  is  needed  for  the  nourishment  of 
the  body. 

A  strong,  hearty  person  may  eat  half  a  pound  or  so  of 
meat  daily ;  yet  he  should  take  other  foods,  such  as  bread, 
oatmeal,  beans,  rice,  and  milk.  These  foods  are  all  good, 
all  cheap,  all  digestible,  and  all  palatable. 

Vegetable  foods  are  less  stimulating  than  animal.  Hence 
they  are  more  suitable  for  children,  for  whom  the  plainest 


124  OUR  BODIES   AND   HOW  WE   LIVE 

and  simplest  diet  is  the  best.  It  is  much  better  for  a  child 
to  go  to  bed  on  a  supper  of  oatmeal,  baked  apples,  or  bread 
and  milk  than  after  one  of  cake,  pie,  and  fried  meat. 

Students  must  also  attend  carefully  to  their  diet.     It  is 
much  better  to  begin  a  day's  study  with  a  breakfast  of  oat- 
meal, stale  bread,  a  soft-boiled  egg,  and  a  glass  of  milk 
.  than  with  one  of  strong  coffee,  sausage,  and  hot  biscuit. 

175.  When  to  eat.    Three  meals  a  day  should  be  eaten 
at  regular  times.     These  should  be  arranged  according  to 
one's  occupation   as  far  as   possible.     The  stomach,  like 
other  organs,  does  its  work  best  when  its  tasks  are  done 
at  regular  periods.     Hence  regularity  in  eating  is  of  the 
utmost  importance. 

Eating  between  mealtimes  should  be  strictly  avoided, 
for  it  robs  the  stomach  of  its  needed  rest.  Food  eaten 
when  the  body  and  mind  are  tired,  is  not  well  digested. 

Rest,  even  for  a  few  minutes,  should  be  taken  before 
eating  a  full  meal.  It  is  a  good  plan  to  lie  down,  or  sit 
quietly  and  read,  for  fifteen  minutes  before  eating. 

The  state  of  the  mind  has  a  great  deal  to  do  with  diges- 
tion. Sudden  fear  or  joy,  or  unexpected  news,  may  take 
away  the  appetite  at  once.  Hence,  so  far  as  we  can,  we 
should  laugh  and  talk  at  our  meals,  and  drive  away  all 
anxious  thoughts  and  unpleasant  topics  of  discussion.  If 
hunger  is  a  good  sauce,  so  also  is  a  hearty  laugh. 

176.  The  Time  to  eat.    We  should  not  eat  a  hearty  meal 
for  at  least  two  hours  before  going  to  bed.     We  should 
make  it  a  point  not  to  omit  a  meal  unless  forced  to  do  so. 
Children,  and  even  grown-up  people,  often  have  the  bad 
habit  of  going  to  school  or  to  work  in  a  hurry,  without 
eating  any  breakfast.     There  is  sure  to  be  an  "all-gone" 
feeling  at  the  stomach  before  another  mealtime. 


THE    DIGESTION    OF   FOOD  12$ 

Severe  exercise  and  hard  study  just  after  a  full  meal  are 
very  apt  to  check  digestion.  The  reason  is  plain :  after  a 
full  meal,  extra  blood  is  needed  to  help  the  stomach  digest 
its  food.  If,  in  addition  to  this,  extra  blood  is  needed  to 
help  the  muscles  or  brain,  digestion  will  be  hindered,  and  a 
feeling  of  dullness  and  heaviness  follows.  This,  in  time, 
often  results  in  poor  digestion,  or,  as  it  is  often  called,  indi- 
gestion or  dyspepsia. 

177.  Hints  about  Eating.  Eat  slowly,  and  thoroughly 
chew  the  food.  Do  not  take  too  much  drink  with  the  food. 
Our  teeth  were  made  to  chew  our  food,  arid  the  saliva  to 


FIG.  81.     Superficial  Lymphatics  of  the  Finger. 

moisten  it  and  help  digestion.  If  the  food  is  well  chewed, 
the  saliva  and  the  gastric  juice  act  more  readily.  It  is  not 
only  bad  manners  to  eat  rapidly,  but  it  is  a  violation  of  the 
simplest  law  of  digestion. 

If  we  take  too  much  drink  with  our  meals,  the  flow  of  the 
saliva  is  checked,  and  digestion  is  thus  hindered.  Rapid 
eating,  with  a  great  deal  of  drink  to  wash  down  the  food, 
is  almost  sure  to  result  in  dyspepsia. 

Do  not  take  food  and  drink  too  hot  or  too  cold.  Hot 
bread  and  hot  tea  and  coffee  often  injure  the  enamel  of  the 
teeth,  and  disturb  the  action  of  the  stomach.  If  the  food 
and  drink  are  taken  too  cold,  undue  heat  is  taken  from  the 
stomach,  and  digestion  is  delayed. 


126  OUR   BODIES   AND   HOW  WE   LIVE 

It  is  not  wise  to  bolster  a  flagging  appetite  with  highly 
spiced  food  and  bitter  drinks.  An  undue  amount  of  pepper, 
mustard,  horse-radish,  pickles,  fancy  meat  dressings,  and 
highly  seasoned  sauces  may  stimulate  digestion  for  a  time, 
but,  used  in  excess,  they  soon  weaken  it. 

177  a.  Proper  Care  of  the  Bowels.  Irregularity  in  eating,  the 
eating  of  rich  pastry,  too  much  finely  bolted  flour,  and  not 
enough  fruit  and  vegetables,  negligence  or  carelessness  in  at- 
tending to  a  regular  daily  evacuation  of  the  bowels,  lead  to  the 
very  common  and  distressing  trouble  known  as  constipation. 

Do  not  get  into  the  habit  of  using  any  of  the  numerous 
proprietary  medicines  to  secure  a  proper  action  of  the  bowels. 
For  the  most  part  they  are  only  of  benefit  for  the  time  and 
rarely  remove  the  cause  of  constipation. 

We  must  pay  strict  attention  to  the  proper  action  of  the 
bowels.  The  formation  of  a  regular  habit  is  of  the  utmost 
importance.  The  bowels  can  be  trained  to  act  at  a  certain 
time  every  day.  Take  great  pains  to  eat  enough  coarse  food, 
such  as  oatmeal,  corn  bread,  vegetables,  stewed  prunes,  dates, 
figs,  etc.  Drink  a  glass  of  water  just  after  getting  out  of  bed 
in  the  morning.  Vigorous  muscular  exercise  is  a  valuable  help. 

178.  Care  of  the  Teeth.  The  teeth  should  be  thoroughly 
cleansed  night  and  morning  with  a  soft  brush  #nd  warm 
water.  Castile  soap  and  some  simple  tooth  powder  with 
no  grit  in  it  may  be  used.  The  brush  should  be  used  on 
the  inner  side  or  back  of  the  teeth  as  well  as  on  the  front. 

Great  care  should  be  taken  in  the  use  of  wooden  tooth- 
picks. What  is  known  as  surgeon's  floss  or  silk,  or  even 
common  silk  thread,  when  drawn  between  the  teeth,  is 
quite  effective  in  removing  particles  of  food. 

The  enamel  if  once  broken  or  destroyed  is  never  renewed. 
The  tooth  is  left  to  decay,  slowly  but  surely;  hence  we 


THE   DIGESTION    OF   FOOD  127 

must  be  on  our  guard  against  certain  things  which  may 
injure  the  enamel. 

Picking  the  teeth  with  pins  and  needles  is  hurtful.  We 
should  never  crack  nuts,  crush  hard  candy,  or  bite  off  stout 
thread  with  the  teeth.  The  continued  use  of  gritty  and 
cheap  tooth  powders,  and  very  hot  food  and  drink  often 
injure  the  enamel. 

The  greatest  care  should  be  taken  in  saving  the  teeth. 
The  last  resort  of  all  is  to  lose  a  tooth  by  having  it  extracted. 
A  skilled  dentist  can  save  almost  anything  in  the  form  of 
a  tooth. 

179.  Effect  of  Alcohol  upon  Mucous  Membranes.    Alcohol 
is  a  distinct  irritant  of  the  mucous  membranes.    Thus,  when 
raw  spirit  is  taken  into  the  mouth,  it  causes  a  burning 
sensation.     When  diluted  it  does  the  same  thing,  but  of 
course  in  a  less  irritating  way.     By  this  irritation  the  epi- 
thelial cells  of  the  mucous  membranes  of  the  mouth,  as 
well  as  the  salivary  glands,  secrete  an  unusual  amount  of 
water.     This  gives  rise  to  a  sense  of  dryness  and  of  thirst.1 
The  mucous  membrane  of  the  stomach  is  irritated  in  a 
similar  way. 

180.  General  Effect  of  Alcohol  on  the  Stomach.     Alcohol 
acts  as  a  mild  or  powerful  irritant  of  the  stomach  accord- 
ing as  it  is  taken  diluted  or  strong.     Its  habitual  use  leads 
to  distressing  forms  of  disease  of  the  stomach.     If  we  could 
look  into  the  stomach,  as  Dr.  Beaumont  looked  into  the 
stomach  of  Alexis  St.  Martin,  just  after  taking  a  drink  of 
raw  spirit,  we  should  find  that  the  inner  surface  would  be 

1  A  noted  French  physiologist,  M.  Lancereaux,  has  found  that  the  use 
of  alcoholic  drinks  produces  a  softening  of  the  salivary  glands,  together 
with  other  changes  in  the  tissue  composing  them.  This  causes  alterations 
in  the  saliva  itself  and  accounts  for  the  dryness  of  the  mouth  so  common 
among  persons  addicted  to  the  use  of  alcohol. 


128  OUR  BODIES   AND   HOW  WE    LIVE 

bright  red  where  the  alcohol  touched  it,  —  far  more  so 
than  after  taking  food.  Alcohol  irritates  the  lining  of  the 
stomach  and  dilates  the  tiny  blood  vessels. 

181.  Effect  of  Alcohol  on  the  Digestive  Powers  of  the 
Gastric  Juice.      Alcohol,   like   any  other    irritant   of   the 
stomach,  causes  the  gastric  juice  to  flow  in  an  excessive 
amount,  as  the  eye,  when  injured,  becomes  flooded  with 
tears.     The  digestive  power  of  the  gastric  juice  is  at  the 
same  time  either  diminished  or  seriously  impaired  by  the 
precipitation  of  its  pepsin.     This  hinders  digestion,  because 
the  solvent  power  of  the  gastric  juice  is  diminished. 

If  this  unnatural  excitement  of  the  glands  of  the  stomach 
is  kept  up  for  some  time,  an  extra  amount  of  useless  work 
is  thrown  upon  the  gastric  glands  and  they  become  less 
able  to  do  their  normal  work. 

The  structural  alterations  that  the  habitual  use  of  alco- 
hol may  induce,  and  the  action  of  this  agent  on  the  pepsin, 
may  seriously  impair  the  digestive  power.  Hence  it  is  that 
those  who  are  habitual  consumers  of  alcoholic  liquors  often 
suffer  from  disorders  of  digestion.  Heartburn,  water  brash, 
acid  stomach,  and  a  peculiar  retching  in  the  morning  may 
thus  be  produced. 

If  the  amount  of  alcohol  be  increased,  or  the  repetition 
become  frequent,  some  part  of  it  undergoes  acid  fermen- 
tation in  the  stomach,  and  acid  eructations  or  vomitings 
occur.  With  these  disturbances  may  be  associated  loss  of 
appetite,  feeble  digestion,-  sallowness,  mental  depression, 
and  headache. 

182.  The  Final  Effect  upon  the   Stomach  of  the  Long- 
Continued  Use   of  Alcohol.     Now,    when   these    alcoholic 
liquors  are  poured  into  the  stomach  for  days,  weeks,  and 
even  for  years,  it  is  no  wonder  that  their  long-continued 


THE   DIGESTION   OF   FOOD  129 

use  causes  the  coats  of  the  stomach  to  become  altered  in 
their  structure.  There  is  a  chronic  inflammation  of  the 
inner  coats,  the  walls  of  the  stomach  become  thicker  and 
harder,  and  traces  of  ulceration  are  often  found.  Because 
the  stomach  is  thus  inflamed  and  unable  to  digest  food 
properly  from  the  habitual  use  of  strong  drink,  many  other 
important  organs  of  the  body  suffer  as  a  result.1 

183.  The  Case  of  Alexis  St.  Martin.  The  effect  of  alco- 
holic liquors  upon  gastric  digestion  was  studied  many  years 
ago  by  Dr.  Beaumont  and  others,  in  the  case  of  Alexis 
St.  Martin,  a  French  Canadian.  This  man  met  with  a 
gunshot  wound  which  left  a  permanent  opening  into  his 
stomach,  guarded  by  a  little  valve  of  mucous  membrane, 
Through  this  opening  the  lining  of  the  stomach  could  be 
seen,  the  temperature  ascertained,  and  numerous  experi- 
ments made  as  to  the  digestibility  of  various  kinds  of  food. 
In  this  remarkable  case  it  was  observed  by  looking  directly 
into  his  stomach  that  when  a  wholesome  dinner  was  digest- 
ing in  good  order,  a  glass  of  gin  arrested  the  process,  which 
was  not  continued  until  the  alcohol  had  passed  out  of  the 
stomach. 

1  Nothing  could  be  further  removed  from  the  truth  than  the  popular 
notion  that  alcohol,  at  least  in  the  form  of  certain  wines,  is  helpful  to  diges- 
tion. Roberts  showed,  years  ago,  that  alcohol,  even  in  small  doses,  dimin- 
ished the  activity  of  the  stomach  in  the  digestion  of  proteids.  Gluzinski 
showed,  ten  years  ago,  that  alcohol  causes  an  arrest  in  the  secretion  of 
pepsin,  and  also  in  its  action  upon  food.  Wolff  showed  that  the  habitual 
use  of  alcohol  produces  disorder  of  the  stomach  to  such  a  degree  as  to 
render  it  incapable  of  responding  to  the  normal  excitation  of  food. 
Blumenau  says  that  alcohol  manifests  a  decidedly  unfavorable  influence  on 
the  course  of  normal  digestion,  even  when  taken  in  small  quantities,  and 
injures  the  normal  digestive  functions.  Hugounence  found  that  all  wines, 
without  exception,  prevent  the  action  of  pepsin  upon  proteids.  The  most 
harmful  are  those  which  contain  large  quantities  of  alcohol,  cream  of  tartar, 
or  coloring  matter.  —  WINFIELD  S.  HALL,  M.D.,  Professor  of  Physiology 
in  Northwestern  University  Medical  School,  Chicago. 


130  OUR   BODIES   AND   HOW  WE   LIVE 

Many  experiments  have  been  made  by  drawing  off  the 
contents  of  the  stomach  with  a  siphon,  during  various  stages 
of  digestion.  When  alcohol  had  been  taken  it  was  found 
that  the  strong  drink  suspended  the  digestion  of  food  for 
some  time  while  it  remained  in  the  stomach,  and  that  only 
after  the  alcohol  left  the  stomach  did  digestion  go  on  at 
a  fair  rate.1 

1  Under  the  influence  of  alcohol,  the  acidity  of  the  gastric  juice  and 
the  quantity  of  hydrochloric  acid,  as  well  as  the  digestive  power  of  the 
gastric  juice,  is  diminished.  This  enfeebling  of  the  digestion  is  especially 
pronounced  in  persons  accustomed  to  the  use  of  alcohol.  —  PROFESSOR 
KOCHLAKOFF,  St.  Petersburg. 

When  constantly  irritated  by  the  direct  action  of  alcoholic  drinks,  the 
stomach  gradually  undergoes  lasting  structural  changes.  Its  vessels  remain 
dilated  and  congested,  its  connective  tissue  becomes  excessive,  and  its 
power  of  secreting  gastric  juice  diminishes.  —  H.  NEWELL  MARTIN,  M.D. 

At  last  the  alcohol  enters  the  stomach.  Wherever  it  touches  it  causes 
irritation,  then  paralysis  of  the  nerves  and  congestion  of  the  mucous  mem- 
branes. It  mixes  with  the  gastric  juice  and  diminishes  its  digestive  power. 
At  length  it  comes  to  pass  that  the  stomach  can  no  longer  fulfill  its  normal 
functions.  It  becomes  flabby  and  inert ;  digestion  becomes  slow  and  diffi- 
cult ;  the  appetite  is  lost.  Soon  after,  the  mucous  membrane,  losing  its 
resisting  power,  corrodes,  small  ulcers  appear,  and  the  condition  becomes 
worse.  —  DR.  BIENFAIT,  Liege. 

Further  serious  disturbances  of  the  digestive  organs  are  found  not  infre- 
quently among  children,  consequent  upon  the  use  of  alcohol ;  but  it  is  still 
more  common  to  find  slight  digestive  troubles  noticeably  increased  by  giving 
children  alcohol  to  cure  them.  —  ADOLF  FRICK,  M.D.,  Zurich. 

Sir  Henry  Thompson,  in  a  recent  work  on  Diet  in  Relation  to  Health, 
gives  the  result  of  some  personal  experience  in  the  use  of  alcohol  with 
meals.  Thirty-two  years  ago,  at  the  age  of  fifty-two,  he  gave  up  the  use 
of  alcohol.  Five  or  six  years  ago,  for  the  sake  of  the  experiment,  he  tried 
the  effect  of  a  claret  glass  of  good  wine  at  dinner  every  day  for  two  months. 
Sick  headaches  and  pains  in  the  joints,  from  which  he  had  suffered  in 
early  life,  came  back  until  he  again  abstained.  After  abandoning  alcohol 
the  joints  gradually  lost  their  stiffness  and  ultimately  became  as  supple 
and  mobile  as  they  were  in  youth  and  continue  absolutely  so  to  this  day. 
Dr.  Thompson  says  he  is  not  an  exception,  and  he  claims  that  a  large  class 
of  active  men  possess  a  more  or  less  similar  temperament. 


THE   DIGESTION   OF   FOOD  131 

184.  Effect  of  Alcohol  on  the  Liver.    When  alcohol  is 
taken  up  by  the  blood  vessels  of  the  stomach,  it  is  carried 
directly  to  the  liver,  and  filtered  through  this  largest  and 
most  important  organ  before  it  reaches  the  heart.    This,  as 
we  shall  learn,  is  a  part  of  the  portal  circulation  (Sec.  210). 
Hence  the  poisonous  effects  of  alcohol  are  strongly  marked 
in  the  liver,  especially  among  hard  drinkers. 

The  blood  vessels  of  the  liver  are  overworked,  and  the 
capillaries  engorged  with  blood.  This  causes,  first,  an 
enlargement  of  the  liver,  and  then  a  shriveling  of  the  sub- 
stance of  the  organ,  together  with  a  rough  and  bunchy 
surface. 

185.  The  Effect  of  Tobacco  on  Digestion.     The  use  of 
tobacco,  either  in  smoking  or  chewing,  causes  the  glands 
of  the  mouth  to  secrete  an  unnatural  amount  of  saliva ; 
this,  in  time,  weakens  them  and  causes  dryness  of  the 
throat.     It  may  also  interfere  with  digestion.     Very  fre- 
quently smoking  leads  to  indigestion,  which  can  only  be 
cured  by  abandoning  tobacco.    Physicians  meet  with  numer- 
ous cases  of  dyspepsia  caused  by  the  use  of  tobacco  in 
some  one  of  its  forms.1 

186.  Smoking  Cigarettes.  Cigarettes  may  seriously  impair 
general  nutrition,  causing  loss  of  appetite,  fullness  of  the 
stomach,  nausea,  vomiting,  and  dyspepsia.    In  many  cases 
so  marked  are  these  symptoms  of  impaired  nutrition  that 
they  produce   a   typical    condition    known    as    "cigarette 
cachexia." 

1  One  of  the  more  common  effects  of  absorption  of  tobacco  products  is 
to  impair  the  appetite  and  weaken  digestion.  —  H.  NEWELL  MARTIN,  M.D. 


132  OUR   BODIES   AND   HOW  WE   LIVE 


QUESTIONS  ON  THE  TEXT 

I.  What,  in  a  general  way,  is  the  object  of  digestion?     2.  What 
is  the  alimentary  canal  ?    3.  Mention  the  various  parts  of  the  alimen- 
tary canal.     4.  What  takes  place  in  the  mouth?     5.  Describe  the 
process  of  chewing,  or  mastication.     6.  Describe  the  structure  of 
the  teeth.     7.  Mention  the  number  and  situation  of  the  teeth,  giving 
the  name  of  each.     8.  What  are  the  salivary  glands?     9.  What  is 
saliva,  and  what  is  its  action  ?     10.  What  is  meant  by  secretion  and 
excretion  ? 

II.  Describe  the  process  of  swallowing  food.     12.  What  is  the 
epiglottis,    and   what   useful    purpose   does    it    serve?     13.  Explain 
the  action  of  the  gullet,  or  food  pipe.     14.  Describe  the  stomach. 
15.  What  happens  when  the  food  reaches  the  stomach  ?     16.  What 
is  gastric  juice,  and  how  is  it  secreted  ?     17.  Describe  the  action  of 
the  gastric  juice.     18.  Describe  the  small  intestine.     19.  What  is  the 
liver?     20.  How  does  bile  help  in  digestion  ? 

21.  What  is  pancreatic  juice,  and  what  is  its  action  ?  22.  Describe, 
in  a  general  way,  the  process  of  absorption.  23.  What  part  do  the 
lacteals  play  in  the  process  of  absorption  ?  24.  What  is  the  thoracic 
duct,  and  what  is  its  use  ?  25.  What  are  the  lymphatics,  and  what 
work  do  they  do  ?  26.  Describe  the  spleen  and  other  ductless  glands. 
27.  Describe  absorption  by  the  blood  vessels.  28.  What  is  the  large 
intestine  and  what  purpose  does  it  serve  ?  29.  Upon  what  does  the 
required  quantity  of  food  depend?  30.  What  are  some  of  the  ill 
effects  of  eating  too  much  ? 

31.  What  should  guide  us  as  to  what  we  should  eat  ?  32.  Describe 
in  full  when  we  should  eat.  33.  What  can  you  say  about  the  time 
to  eat  ?  34.  Mention  other  hints  about  eating.  35.  Give  some  hints 
about  the  care  of  the  teeth.  36.  What  are  some  of  the  effects  of 
alcoholic  liquors  upon  the  stomach  ?  37.  What  are  some  of  the  effects 
of  the  long-continued  use  of  alcohol  upon  the  structure  of  the  stomach? 
38.  What  is  the  effect  of  alcohol  on  the  liver?  39.  Describe  the 
effect  of  tobacco  on  digestion.  40.  What  is  the  effect  of  smoking 
cigarettes  on  digestion? 


CHAPTER  VII 
THE  CIRCULATION  OF  THE  BLOOD 

187.  The  Use  of  Blood.     Every  child  knows  that  if  he 
clits  his  finger,  or  even  pricks  it  with  a  needle,  the  blood 
will  flow.     What  is  true  of  the  finger  is  also  true  of  every 
other  part  of  the  body,  except  the  outermost  layer  of  the 
skin,  the  hair,  and  the  nails. 

The  tiny  blood  vessels  go  everywhere,  through  the  mus- 
cles and  nerves,  over  and  within  the  brain,  through  every 
part  of  every  bone, — the  blood  flows  everywhere.  Wher- 
ever it  goes,  the  blood  has  something  to  bring  to  the  tissues 
and  something  to  carry  away. 

The  blood,  in  its  ceaseless  round,  not  only  brings  new 
material  for  repair,  but  it  also  becomes  a  kind  of  sewer 
stream  that  carries  waste  matters  to  organs  whose  duty  it 
is  to  cast  them  out  of  the  body. 

188.  Properties  of  Blood.     The  blood  is  a  red,  somewhat 
sticky  fluid,  thicker  than  water.      It  has  a  peculiar  smell 
and  a  saltish  taste.     If  we  look  at  a  small  drop  of  freshly 
drawn  blood  under  a  microscope,  we  shall  see  that  it  is  not 
so  simple  as  it  looks.     It  consists  of  fluid  of  a  light  straw 
color,  called  the  plasma,  and  an  enormous  number  of  little 
bodies  called  corpuscles,  floating  in  the  liquid.     These  cor- 
puscles are  of  two  kinds,  red  and  white. 

189.  Why  the  Blood  looks  Red.     The  red  color  of  the 
blood  is  due  to  millions  of  little  red  corpuscles  which  float 

133 


134 


OUR   BODIES   AND   HOW   WE   LIVE 


about  in  the  plasma.  In  the  same  way,  a  clear  white  glass 
bottle  filled  with  red  beads  and  water  would  look  uniformly 
red  at  a  short  distance.  There  are  about  five  hundred  of 
the  red  corpuscles  to  one  of  the  white  corpuscles. 

The  red  corpuscles  contain  iron  combined  with  proteid. 
The  red  substance  thus  formed  combines  readily  with  oxy- 
gen and  makes  the 
blood  scarlet. 

Experiment  38.  To 
illustrate  in  a  general 
way  that  blood  is  really  a 
mass  of  red  bodies  which 
give  the  red  color  to  the 
fluid  in  which  they  float. 
Fill  a  clean  white  glass 
bottle  two  thirds  full  of 
little  red  beads,  and  then 
fill  the  bottle  full  of  water. 
At  a  short  distance  the 
bottle  appears  to  be  filled 
with  a  uniformly  red 
^^S^ML_^^^  liquid. 

FIG.  82.     Human  Blood  Corpuscles,  as  190.    The  Red  Cor- 

seen  under  the  Microscope.  ^     ^               ^ 

Magnified  1000  diameters. 

The  dark  circular  disks  are  the  red  corpuscles.    Near  red  COrpUSClCS  are  CirCU- 

the  center  two  white  corpuscles  are  seen,  with  their  lar   disks,  resembling 

nuclei  stained  so  that  they  look  black.  .                  r 

somewhat   pieces   of 

money.  Their  form  is  not  unlike  that  of  an  india-rubber 
air  cushion  when  blown  up  with  air.  They  are  not  hard, 
but  are  like  tiny  pieces  of  red  jelly.  They  are  so  elastic 
that  they  can  squeeze  through  narrow  places  and  then  at 
once  return  to  their  own  shape. 

The  red  corpuscles  are  so  very  small  that,  if  we  had 
fingers  delicate  enough  to  handle  them,  we  could  place 


THE   CIRCULATION    OF   THE   BLOOD  135 

some  fifty  thousand  of  them  on  the  head  of  a  pin.  It  is 
said  that  some  five  million  of  them  will  float  round  in  a 
single  drop  of  blood.  If  placed  in  a  row  side  by  side,  it 
would  take  about  thirty-two  hundred  of  them  to  measure 
one  inch.  Under  the 

microscope,    the    sides    of  , 

these    disks    stick    to    one  i  ^Jlb^  J 

another  in  rolls,  like  so 
many  coins. 


FIG.  83.  Lateral  Section  of  the 
Right  Chest,  showing  the  Rela- 
tive Position  of  the  Heart  and 
its  Great  Vessels,  the  CEsoph- 
agus  and  the  Trachea. 

A,  a  muscle  which  aids  in  pushing  the 
food  down  the  oesophagus;  £,  oesoph- 
agus; C,  section  of  the  right  bron- 
chus ;  D,  two  right  pulmonary  veins ; 
E,  great  azygos  vein  crossing  cesoph- 
agus  to  empty  into  the  superior 
vena  cava;  F,  thoracic  duct;  H, 
thoracic  aorta ;  K,  lower  portion  of 
oesophagus  passing  through  the  dia- 
phragm ;  Z,,  diaphragm  as  it  appears 
in  sectional  view,  enveloping  the 
heart ;  M,  inferior  vena  cava,  pass- 
ing through  diaphragm  and  empty- 
ing into  right  auricle;  N,  right 
auricle ;  O,  section  of  right  branch 
of  the  pulmonary  artery ;  P,  aorta  ; 
R,  superior  vena  cava ;  S,  trachea. 


191.  The  Work  done  by  the  Red  Corpuscles.    The  red 

corpuscles  absorb  oxygen  in  the  lungs  and  carry  it  to  the 
various  tissues  of  the  body,  which  are  greedy  for  it.  Night 
or  day,  whether  we  are  asleep  or  awake,  millions  of  these 


136  OUR  BODIES   AND   HOW  WE    LIVE 

tiny  oxygen-carriers  are  as  busy  as  bees,  swirling  through 
the  blood  vessels. 

The  blood  has  been  beautifully  called  "the  river  of  life." 
The  red  corpuscles'  may  be  compared  to  a  countless  fleet  of 
little  boats  which  are  constantly  floating  along  in  this  river. 

192.  The  White   Corpuscles.     The   white   corpuscles   are 
slightly  larger  than  the  red,  and  are  not  flattened.     They 
may  sometimes  be  kept  alive  under  the  microscope,  and 
may  be  seen  rolling  and  tumbling  about.     At  one  time 
they  are  round  like  a  ball,  and  of  such  a  size  that  it  would 
take  about  twenty-five  hundred  of  them  to  measure  one 
inch.     Shortly  afterwards,  however,  they  change  this  form 
and  become  pear  shaped,  three  sided,  and  so  on,  in  endless 
variety  (Fig.  82). 

The  white  corpuscles  serve  as  a  kind  of  scavenger  for 
the  body.  They  creep  out  of  "the  blood  vessels  into  the 
tissues  and  there  pick  up  tiny  bits  of  foreign  substances. 
These  corpuscles  seem  to  be  warrior  cells,  forever  fighting 
against  the  invasion  of  bacteria. 

Experiment  39.  To  show  the  blood  corpuscles.  Place  a  small  drop 
of  blood  (easily  obtained  by  pricking  the  finger  with  a  needle)  upon 
a  clean  slip  of  glass  and  cover  with  thin  glass,  such  as  is  ordinarily 
used  for  microscopic  purposes.  The  blood  thus  spread  out  into  a 
film  may  be  readily  examined  with  a  moderately  powerful  microscope. 
At  first  the  red  corpuscles  will  be  seen  as  pale,  disklike  bodies  float- 
ing in  the  clear  fluid.  Soon  they  will  be  observed  to  stick  to  each 
other  by  their  concave  faces,  so  as  to  form  rows.  Here  and  there  a 
white  corpuscle  may  be  seen  among  the  red  ones  (Fig.  82). 

193.  The  Clotting  of  Blood.     If  a  basin  of  fresh  blood  is 
allowed  to  stand  for  a  short  time,  it  will  separate  into  two 
parts  :  one,  a  sticky,  jellylike  mass,  called  the  clot,  settles 
to  the  bottom;   the  other,  a  straw-colored,  watery  fluid, 


THE   CIRCULATION    OF   THE   BLOOD 


137 


PAROTID  GLAND 


COMMON  CAROTID  ARTCR 
EXTERNAL  JUCULAfUfCIN 
INTERNAL  JUGULAR  VEIN 


BftACHIAL  ARTCP 
BKACHIAL  VEIN  '" 


RADIAL    AKTE 
RADIAL    VEIN 


FIG.  84.     Principal  Muscles  on  the  Right,  Certain  Organs  of  the  Chest  and 
Abdomen,  and  the  Larger  Blood  Vessels  on  the  Left. 


138  OUR   BODIES  AND   HOW  WE   LIVE 

called  the  serum,  remains  at  the  top.  This  change  of 
the  blood,  after  it  is  drawn  from  the  body,  into  a  jelly- 
like,  semisolid  mass,  is  called  the  "clotting,  or  the  coagulation, 
of  the  blood. 

The  watery  part,  or  serum  as  it  is  called,  is  blood  from 
which  the  corpuscles  have  been  removed  by  the  process  of 
clotting.  It  is  largely  made  up  of  water  in  which  albumin 
is  dissolved. 

The  clot  consists  mainly  of  two  substances,  —  the  cor- 
puscles and  a  network  of  white,  tough,  fibrous  threads, 
called  fibrin.  The  clotting  of  blood  is  not  yet  fully  under- 
stood, but  it  is  thought  to  be  due  in  part  to  the  formation 
of  this  fibrin.  The  corpuscles  get  snarled  in  the  meshes  of 
the  fibrin,  and  thus  the  clot  is  formed. 

194.  Why  the  Clotting  of  Blood  is  Important.  The  fact 
that  blood  clots  when  shed  is  one  of  its  most  striking  prop- 
erties. It  is  of  the  most  vital  importance.  When  a  person 
receives  a  severe  wound  he  would  bleed  to  death  unless 
clotting  set  in.  Nature  in  this  way  plugs  up  the  wound 
with  clots  of  blood  and  prevents '  too  much  bleeding. 
Blood  does  not  clot  within  the  healthy  vessels.  It  may  do 
so  in  certain  diseased  conditions.1 

Experiment  40.  Put  two  or  three  drops  of  fresh  blood  on  the 
bottom  of  a  little  white  butter  plate.  Place  the  plate  in  a  saucer 
which  has  a  little  water  in  it  and  cover  it  with  an  inverted  goblet. 
Take  off  the  cover  in  five  minutes,  and  the  drop  has  set  into  a  jellylike 
mass.  In  half  an  hour  a  little  clot  will  be  seen  in  the  watery  serum. 

1  Thus,  in  those  who  suffer  from  enlarged  or  varicose  veins,  a  clot  may 
sometimes  form  in  the  veins  of  the  leg.  Snake  poison  may  act  to  cause 
the  blood  to  clot  within  the  vessels.  In  some  very  rare  cases  there  are 
people  born  in  whom  the  blood  has  little  or  no  power  of  clotting.  These 
are  known  as  "  bleeders,"  and  with  them  a  slight  cut  on  the  finger  or  even 
a  pin  scratch  may  prove  a  serious  matter,  owing  to  the  loss  of  blood. 


THE   CIRCULATION    OF    THE   BLOOD 


139 


195.  General  Plan  of  Circulation.     Since  all  the  tissues 
stand  in  such  constant  need  of  blood,  there  must  be  some 
special  machinery  by  which  this  "river  of  life  "  is  made  to 
keep  up  its  constant  flow  through  every  nook  of  the  body. 
Let  us  now  begin  the 

study  of  this  apparatus. 

In  the  first  place, 
there  is  in  the  chest  a 
little  pump  called  the 
heart,  from  which  tubes 
are  distributed  to  all 
parts  of  the  body. 

One  set  of  tubes, 
called  arteries,  carries 
the  blood  from  the 
heart. 

Another  set  of  tubes, 
called  veins,  brings  the 
blood  back  to  the  heart. 

This  continued  flow 
of  blood  through  the 
body,  to  and  from  the 
heart,  is  called  the  cir- 
culation of  the  blood. 

196.  The  Circulation 
compared  to  the  Water 
Service  of  a  City.     The 
way  in  which  blood  is 

made  to  flow  through  vessels  of  the  body  may  be  compared  in 
a  general  way  to  the  manner  in  which  water  is  supplied  to  a 
city.  The  heart  is  the  pumping  engine  which  forces  the  blood 
into  the  main  pipes  for  the  supply  of  the  several  districts. 


FIG.  85.     Anterior  View  of  the  Heart. 

A,  superior  vena  cava  ;  B,  right  auricle  ;  C,  right 
ventricle ;  Z),  left  ventricle ;  E,  left  auricle ; 
F,  pulmonary  vein ;  H,  pulmonary  artery ; 
K,  aorta  ;  L,  right  subclavian  artery ;  M,  right 
common  carotid  artery ;  N,  left  common  carotid 
artery. 


140 


OUR   BODIES   AND   HOW  WE   LIVE 


As  through  a  city  the  great  water  mains  branch  and 
subdivide  into  smaller  pipes  for  the  supply  of  districts, 

streets,  houses,  and  rooms,  so 
in  the  body  the  blood  vessels 
divide  over  and  over  again  to 
furnish  blood  to  the  smallest 
organs  and  the  most  remote 
parts  of  the  tissues.  The  par- 
allel ends  here.  The  water 
supplied  to  the  city  does  not 
return  to  the  pumping  station, 
whereas  the  blood  returns  to 
the  heart. 

When  the  blood  has  been 
pumped  through  every  part  of 
the  body,  and  has  given  to  it 
the  food  which  it  needs,  it  re- 
ceives from  the  tissues  certain 
waste  matters,  the  result  of 

wear  and  tear.     The  blood  is 

,  £JL  £  .  , 

now  no  longer  fit  for  nourish- 

A.  B.    right    pulmonary   veins;    S,  ,     •,      .    •                    ,.,             i  •     i 

openings   of    the   left   pulmonary^  ment,  but   IS   more   like   a   kind 

veins  ;£,  D,  C,  aortic  valves  ;  R,  of     sewer     Stream     laden     With 

aorta  ;   P.  pulmonary   artery  ;    O,  _,,              .       , 

pulmonic  valves  ;  H,  mitral  valve  ;  Waste  matters.       These,  in  dUC 

K,  columns  cames;  M,  right  ven-    time,   are   brought   to  certain 

tricular  cavity.  ,         ,  . 

organs,  as  the  lungs,  the  skin, 
and  the  kidneys,  and  cast  out  of  the  body. 

197.  The  Heart.  The  heart  is  hollow  and  muscular, 
somewhat  like  a  pear  in  shape.  It  is  hung  almost  in  the 
center  of  the  chest,  above  the  diaphragm,  and  is  partly 
overlapped  by  the  lungs.  It  is  about  the  size  of  the 
closed  fist  of  the  person  to  whom  it  belongs. 


FIG.  86.     Cavities  of  the  Heart. 


THE   CIRCULATION   OF   THE   BLOOD  141 

The  apex  of  the  heart  beats  against  the  chest  wall 
between  the  fifth  and  sixth  ribs,  about  an  inch  and  a  half 
to  the  left  of  the  middle  line  of  the  body. 

198.  The  Pericardium.     The  heart  lies  within  a  strong, 
fibrous  membrane  forming  a  kind  of  bag  or  purse  called 
the  pericardium.     This  bag  is  really  double,  with  two  layers, 
one  over  the  other.     The  inner  layer  closely  covers  the 
surface  of  the  heart  and  is  reflected  upon  itself  to  form 
a  sack  without  an  opening. 

Place  your  hand  in  a  stocking  which  has  the  foot  turned 
inwards,  and  your  hand  will  be  covered  by  a  double  coat 
somewhat  as  your  heart  is  by  its  double  bag.1  Between 
the  two  layers  of  the  pericardium  there  is  a  small  quantity 
of  clear  fluid  which  permits  the  parts  to  move  one  upon 
the  other  with  little  friction. 

199.  The  Chambers  of  the  Heart.    The  heart  has  a  mus- 
cular partition  running  down  its  center  from  top  to  bottom, 
separating  the  right  side  from  the  left.     Each  of  these 
sides  has  two  hollow  chambers  or  cavities :   an   upper  one 
called  an  auricle,  from  the  fancied  resemblance  of  one  cor- 
ner to  the  ear  of  a  dog ;  the  other  and  lower  one  called  a 
ventricle.     Hence  there  are  two  upper  chambers  called  auri- 
cles, and  two  lower  chambers  called  ventricles. 

The  heart  is  a  muscle;  hence  it  can  contract.  When 
each  of  its  chambers  contracts,  blood  is  forced  to  flow  into 
the  next  chamber  or  a  blood  vessel,  as  the  case  may  be. 
The  walls  of  the  ventricles  are  stouter  and  stronger  than 

1  We  must  remember,  however,  that  the  leg  of  the  stocking  is  open  at 
the  end  while  the  pericardium  is  closed.  We  may  think  of  the  pericardium 
shielding  the  heart  somewhat  as  the  leather  case  of  a  football  protects  the 
bladder  within  it.  Again,  the  pericardium  is  arranged  about  the  heart  as  a 
boy's  toboggan  cap  covers  his  head. 


142 


OUR  BODIES   AND    HOW  WE   LIVE 


those  of  the  auricles,  and  those  of  the  left  ventricle  are 
much  stouter  than  those  of  the  right  ventricle. 

The  right  auricle  opens  into  the  right  ventricle,  and  the 
left  auricle  into  the  left  ventricle ;  but  there  is  no  connec- 
tion between  the  right 
and  left  cavities  of  the 
heart. 

200.  The  Valves  of 
the  Heart.  The  open- 
ings between  the  aur- 
icles and  ventricles  are 
guarded  by  flaps  of  mem- 
brane, or  little  swing 
doors,  called  valves. 

These  valve  flaps  may 
be  roughly  compared  to 
folding  doors  or  gates, 
which,  by  opening  only 
one  way,  allow  the  blood 
to  flow  in  that  direction 
and  prevent  its  flowing 
in  any  other. 

The  valve  on  the  right 
side  of  the  heart  is  called 


FIG.  87.     Posterior  View  of  the  Heart. 
L.A.,  left  auricle;  R.A.,  right  auricle;  L.V.,  left 


ventricle;  R.V.,  right  ventricle;  ,4,  opening     thg  three-pointed,  Or 
of  the  inferior  vena  cava ;  B,  superior  vena  r 

cava;  C,  right  pulmonary  veins;  D,  left  pul-     tlicUSpid,    Valve. 

The  valve  on  the  left 
looks   somewhat    like   a 
bishop's  miter  ;  hence  it 
is  called  the  mitral  valve. 
These  valves  fall  back  to  let  the  blood  flow  from  the 
auricles  into  the  ventricles,  but  float  up  with  the  blood  so 


monary  veins ;  £,  aorta ;  F,  left  branch  of 
pulmonary  artery ;  G,  great  cardiac  vein ; 
H,  middle  cardiac  vein.  The  cardiac  lym- 
phatics which  follow  the  course  of  the  car- 
diac veins  are  also  shown. 


THE   CIRCULATION   OF   THE   BLOOD  143 

as  to  prevent  the  return  of  the  blood  into  the  auricles. 
The  valves  are  prevented  from  floating  over  into  the  auri- 
cles by  cords  which  tie  them  to  the  ventricles.  These  cords 
may  be  drawn  tight  by  the  contraction  of  the  little  muscles 
in  the  wall  of  the  ventricles  to  which  they  are  attached. 

Between  the  ventricles  and  the  arteries  are  the  half-moon 
shaped,  or  semilunar,  valves. 


FIG.  88.     Muscular  Fibers  of  the  Auricles. 

L~A.,  left  auricle ;  R.A.,  right  auricle ;  A,  opening  of  the  inferior  vena  cava ; 
B,  superior  vena  cava  ;  C,  cardiac  vein  of  right  auricle  laid  open ;  D,  left 
pulmonary  veins;  E,  right  pulmonary  veins;  f,  muscular  fibers  sur- 
rounding the  openings  between  the  left  auricle  and  left  ventricle,  and 
the  right  auricle  and  right  ventricle ;  G,  H,  K,  and  L,  muscular  fibers 
surrounding  the  great  veins  of  the  heart. 

201.  The  Work  of  the  Heart.  The  heart  is  a  wonderfully 
busy  machine,  pumping  away  without  getting  tired,  night  and 
day  for  eighty  years  or  more,  perhaps,  at  the  rate  of  seventy 
strokes  every  minute,  over  forty-two  hundred  times  every  hour, 
and  nearly  thirty-seven  million  beats  every  year.  At  each 


144  OUR   BODIES   AND    HOW  WE    LIVE 

stroke  the  ventricles  pump  about  six  ounces,  or  nearly  fifty 
teaspoonfuls,  of  blood.  About  eighteen  pounds  of  blood  are 
moved  every  minute,  or  twelve  tons  every  day. 

It  is  calculated  that  the  total  amount  of  daily  work  done  by 
the  heart  can  be  represented  by  what  a  man  of  average  weight, 
about  one  hundred  and  fifty  pounds,  would  do  in  running  up  a 
flight  of  forty  steps  forty  times.  While  the  cavities  are  filling 
with  blood,  and  its  muscles  are  relaxed,  the  heart  has  a  brief 
rest ;  otherwise,  it  could  not  keep  up  its  patient  and  tireless 
pumping  of  over  four  thousand  tons  of  blood  every  year,  from 
birth  to  death.1 

202.  The  Blood  Vessels  that  enter  and  leave  the  Heart. 
The  aorta,  the  largest  artery  in  the  body,  springs  from  the 
left  ventricle.  It  carries  the  bright,  pure  blood  from  the 
heart  to  all  parts  of  the  body. 

Four  pulmonary  veins  open  into  the  left  auricle.  Two  of 
these  veins  come  from  the  right  lung  and  two  from  the 
left  lung.  They  bring  back  to  the  heart  the  blood  which 
has  been  combined  with  oxygen  in  the  lungs. 

Two  of  the  largest  veins  in  the  body,  call-ed  the  superior 
vena  cava  and  the  inferior  vena  cava,  open  into  the  right  auricle. 
These  great  veins  pour  into  the  right  auricle  the  dark  blood 
which  has  been  collected  in  various  parts  of  the  body  by 
the  smaller  veins  (Fig.  95). 

The  pulmonary  artery  springs  from  the  right  ventricle. 
Soon  after  leaving  the  heart,  it  splits  into  two  pipes ;  one 
goes  to  the  right  lung,  the  other  to  the  left  lung.  This 
artery  carries  from  the  heart  to  the  lungs  the  dark,  impure 
blood  which  has  been  brought  to  it  by  the  great  veins. 
Its  entrance  is  guarded  by  the  three  semilunar  valves. 

1  It  should  be  remembered  that  the  two  auricles  contract  at  the  same  time 
and  then  the  two  ventricles.  Then  comes  a  pause,  or  state  of  rest,  after 
which  the  auricles  and  ventricles  contract  in  the  same  order  as  before. 


THE   CIRCULATION    OF   THE    BLOOD 


145 


203.  The  Aorta  and  its  Great  Branches.  Branches  of  the 
aorta  carry  blood  from  the  heart  to  the  tissues.  They  are  called 
arteries.  After  leaving  the  heart  the  aorta  rises  towards  the 
neck,  but  soon  curves  downwards  to  form  the  arch  of  the 
aorta.  This  great 
tube  passes  between 
the  lungs  to  the  back, 
then  runs  down  along 
the  spine  through 
the  diaphragm. 

In  the  abdomen  it 
divides  into  two 
branches,  one  of 
which  goes  to  each 
lower  limb. 

Branches  spring- 
ing from  the  arch  of 
the  aorta  supply  the 
head  and  the  arms. 

While  the  aorta 
is  passing  down  the 
spine  it  gives  off 
branches  to  nourish 
the  lungs  and  the 

Showing  the  carotid  artery  and  jugular  vein  on  the 
right  side,  with  some  of  their  main  branches  ;  also 
some  large  nerve  trunks. 


FlG- 


important  organs  of 
the  abdomen. 


Experiment  41.  To  illustrate  how  the  heart  pumps  blood.  Sink 
the  suction  end  of  a  bulb  syringe  into  water.  Press  the  bulb.  As 
the  bulb  expands,  it  fills  with  water;  as  we  press  it  again,  a  valve 
prevents  the  water  from  flowing  back,  and  it  is  driven  out  in  a  jet 
along  the  main  pipe.  The  suction  pipe  represents  the  veins ;  the 
bulb,  the  heart;  and  the  tube  end,  the  arteries. 


146 


OUR   BODIES   AND    HOW  WE   LIVE 


FIG.  90. 


204.  The  Veins.  The  veins  are  the  return  pipes  that 
bring  the  blood  Back  to  the  heart.  They  generally  lie 
near  the  surface  of  the  body,  just  beneath  the  skin.  We 
may  see  them  in  almost  any  part  of  the  body.  Unlike 
the  arteries,  which  gradually  grow 
smaller  and  smaller,  the  veins,  start- 
ing from  the  capillaries,  grow  larger 
and  larger. 

The  veins  of  the  legs  pass  upwards, 
becoming  gradually  larger  by  the  addi- 
tion of  other  branches  in  the  abdomen, 
until  at  last  all  the  united  branches 
are  joined  in  one  great  vein,  which 
empties  into  the  right  auricle  of  the 
heart  (Sec.  202). 

The   venous  blood  from  the  head 
B,  longitudinal  section  of  and  the  arms  empties  into  the  right 

a  vein,  showing  the  valves  -11  ^11 

closed<  auricle  by  another  large  vein. 

As  we  have  learned,  the  four  pul- 
monary veins  carry  the  arterial  blood  from  the  lungs  to  the 
left  auricle  (Sec.  202). 

The  veins  are  abundantly  supplied  with  little  pouch- 
like  folds  or  pockets  which  act  as  valves  to  prevent  the 
backward  flow  of  the  blood.  If  we  press  the  fingers 
along  one  of  the  veins  in  the  arm,  towards  the  hand,  we 
shall  see  a  number  of  little  knots  or  swellings  here  and 
there  along  the  vein.  These  indicate  the  position  of  the 
valves. 

The  blood  thus  forced  back  fills  the  little  pockets  in  the 
vein.  Take  away  the  finger  and  the  knots  will  at  once 
disappear,  because  the  blood  is  left  free  to  flow  towards 
the  heart. 


THE   CIRCULATION   OF   THE   BLOOD  147 

Experiment  42.  Grasp  the  left  wrist  tightly  with  the  thumb  and 
two  fingers  of*  the  right  hand.  Note  the  little  knots  or  swellings  in 
the  veins  on  the  back  of  the  hand,  caused  by  checking  the  flow  of  the 
venous  blood  towards  the  heart.  These  swellings  show  the  position 
of  the  valves  of  the  veins. 

205.  The  Capillaries.  Between  the  ends  of  the  smallest 
arteries  and  the  beginnings  of  the  tiniest  veins  is  a  very 
close  network,  like  the  finest  lace,  with  the  minutest  little 
tubes  for  threads.  These  little  tubes  or  threadlike  vessels 
are  called  capillaries. 

In  reality  the  capillaries  are  as  much  smaller  than  threads 
as  the  smallest  threads  are  smaller  than  cables.  So  close 


FIG.  91.  The  Right  Axillary 
and  Brachial  Arteries,  with 
Some  of  their  Main 
Branches. 


set  are  these  tiny  vessels  that  we  cannot  prick  any  part  of 
the  skin,  even  with  the  finest  needle,  without  wounding 
many  of  them  and  drawing  blood.  They  are  so  small  that 
three  thousand  of  them  placed  side  by  side  would  not,  in 
their  united  width,  measure  more  than  one  inch. 

206.  The  Interchange  between  the  Blood  in  the  Capillaries 
and  the  Lymph  in  the  Tissues.  The  capillaries  are  closed 
vessels.  The  space  between  the  walls  of  the  capillaries 


148  OUR   BODIES  AND   HOW  WE    LIVE 

and  the  cells  of  the  tissues  is  filled  with  a  clear,  watery 
fluid  known  as  lymph. 

As  the  blood  flows  along  the  capillaries,  certain  parts  of 
the  plasma  of  the  blood  filter  through  their  walls  into  the 
lymph,  and  certain  parts  of  the  lymph  filter  in  the  opposite 
direction  through  the  walls  of  the  capillaries  and  mingle 
with  the  blood  current.  A  constant  interchange  of  mate- 
rial is  thus  going  on  between  the  lymph  which  bathes  the 
tissues  and  the  blood  in  the  capillaries. 

In  brief,  the  lymph  acts  as  a  medium  of  exchange  between  the 
blood  and  the  tissues. 

207.  The  General  Course  of  Circulation.     We  are  now 
ready  to  study  the  circulation  as  a  whole,  tracing  the  course 
of  the  blood  from  a  certain  point  until  it  returns  to  the 
same  point.     We  may  conveniently  begin  with  the  portion 
of  blood  contained  at  any  moment  in  the  right  auricle. 

We  may  perhaps  better  understand  the  general  course 
of  circulation  if  we  subdivide  it  into  two  parts :  the  pul- 
monary circulation,  or  circulation  in  the  lungs,  and  the 
systemic,  or  greater,  circulation. 

We  must  keep  clearly  in  mind,  however,  that  there  is 
but  a  single  circulation  in  the  body. 

208.  The  Pulmonary,  or  Lesser,  Circulation.     Two  large 
veins  are  busily  filling  the  right  auricle  with  dark  (venous) 
blood,   collected  from  all  parts  of  the  body.     When  the 
auricle  contracts,  the  blood  cannot  get  back  into  the  great 
veins  because  it  is  flushed  forward  by  the  great  volume 
of   blood    behind    it.     The   door   opening    into    the   right 
ventricle  lies  open,  and  the  blood  flows  through  it  until  it 
is  full. 

The  ventricle  now  begins  to  contract ;  the  tricuspid  valve 
at  once  closes  and  thus  prevents  the  backward  flow  of 


THE   CIRCULATION   OF   THE   BLOOD 


149 


FIG.  92.     Diagram  of  the  Circulation  of  Blood. 

J?.A.,  right  auricle;  L.A.,  left  auricle  ;  J?.V.,  right  ventricle  :  L.V.,  left 
ventricle;  P.A.,  pulmonary  artery;  A,  pulmonary  artery  and  vein 
of  right  lung ;  B,  pulmonary  artery  and  vein  of  left  lung ;  C,  carotid 
artery  to  head,  showing  branch  of  left  subclavian  artery ;  D,  portal 
vein ;  E,  hepatic  vein ;  f,  hepatic  artery ;  G,  superior  vena  cava, 
bringing  blood  from  head  and  upper  limbs  to  right  auricle. 


150  OUR  BODIES   AND    HOW  WE    LIVE 

blood.  The  blood  is  driven  into  the  pulmonary  artery  past 
the  semilunar  valves. 

The  pulmonary  artery  carries  the  blood  to  the  lungs. 
The  dark,  impure  blood  is  driven  along  smaller  and  smaller 
vessels  until  it  reaches  the  capillaries  of  the  lungs.  Here 
it  is,  as  it  were,  spread  out  to  be  purified.  Exposed  to  the 
oxygen  of  the  air,  the  blood  gives  up  carbon  dioxide  and 
other  impurities  and  loses  its  purple  color.  It  takes  up  a 
great  deal  of  the  oxygen  of  the  air  in  exchange,  and  in 
a  purified  state  and  of  a  bright  scarlet  color,  it  comes 
back  to  the  heart  by  the  four  pulmonary  veins  which  pour 
it  into  the  left  auricle. 

209.  The  Systemic,  or  Greater,  Circulation.  From  the 
left  auricle  the  blood  is  forced  past  the  mitral  valve  into 
the  left  ventricle.  As  soon  as  the  left  ventricle  is  full  it 
begins  to  contract.  The  mitral  valve  at  once  closes  and 
blocks  up  the  passage  into  the  left  auricle,  and  the  blood 
has  no  other  way  open  but  past  the  semilunar  valves l  into 
the  aorta. 

The  aorta  and  its  branches,  as  we  already  know,  dis- 
tribute the  blood  through  every  tissue  of  the  body.  From 
the  tissues  it  is  again  returned  by  the  veins  to  the  right 
auricle  of  the  heart,  and  thus  the  round  of  circulation  is 
continually  kept  up. 

Experiment  43.  To  illustrate  some  of  the  phenomena  of  circula- 
tion. Attach  a  piece  of  rubber  tube  about  six  or  eight  feet  long  to 
the  delivery  end  of  a  common  rubber  bulb  syringe. 

To  represent  in  a  very  crude  way  the  resistance  made  by  the  capil- 
laries to  the  flow  of  blood,  slip  the  large  end  of  a  common  glass  medi- 
cine dropper  into  the  outer  end  of  the  rubber  tube.  This  dropper 
has  one  end  tapered  to  a  fine  point. 

1  The  entrance  to  the  aorta  is  guarded  by  three  semilunar  valves  similar 
to  those  at  the  entrance  of  the  pulmonary  artery. 


THE   CIRCULATION   OF   THE   BLOOD 


Place  the  syringe  flat,  without  kinks  or  bends,  on  a  desk  or  table. 
Press  the  bulb  slowly  and  regularly.  The  water  is  thus  pumped  into 
the  tube  in  an  intermittent  manner,  and  yet  it  is  forced  out  of  the 
tapering  end  of  the  glass  tube  in  a  steady  flow. 


FIG.  93.     William  Harvey  demonstrating  the  Circulation  of  Blood  to 
King  Charles  the  First  of  England.1 

210.  The  Portal  Circulation.  The  blood  which  is  brought 
to  the  capillaries  of  the  stomach,  intestines,  spleen,  and  pan- 
creas takes  a  roundabout  course  to  get  back  to  the  heart. 

1  William  Harvey  was  a  famous  English  physician  who  discovered  the 
circulation  of  the  blood,  nearly  three  hundred  years  ago.  This  fine  picture 
represents  the  king  as  witnessing  the  dissection  of  a  doe,  of  which  he  had 
placed  many  at  Harvey's  disposal  while  the  great  physician  was  making 
his  investigations  concerning  the  circulation  of  the  blood. 

The  picture  is  used  by  the  kind  permission  of  William  Wood  &  Co., 
publishers. 


OUR  BODIES   AND   HOW  WE   LIVE 


It  is  collected  into  veins  which  unite  into  a  single  trunk, 
called  the  portal  vein,  which  enters  the  liver. 

The  blood,  now  mingling  with  that  brought  to  the  liver 
by  the  hepatic  artery,  is  carried  by  small  veins  which  at 
length  unite  into  a  large  trunk,  the  hepatic  vein.  This  vein 
pours  the  blood  into  the  inferior  vena  cava,  which  carries 
it  to  the  right  auricle  (Fig.  74). 

This  loop,  as  we  may  call  it,  on  the  systemic  circulation 
is  often  called  the  portal  circulation. 

Experiment  44.  To  show  the  circulation  in  the  web  of  a  frog's 
foot.1  To  show  the  circulation  in  a  frog's  foot  it  is  necessary  to 
hold  the  frog  in  place.  Take  a  piece  of  soft  wood  about  six  inches 

long  and  three  wide.  At  about 
two  inches  from  one  end  cut  a 
hole  half  an  inch  in  diameter  and 
cover  it  with  a  glass  slide,  which 
should  be  let  into  the  wood,  level 
with  the  surface.  Then  wrap  the 
frog  in  a  damp  cheese  cloth,  leaving 
one  foot  exposed.  Next,  fasten 
a  piece  of  thread  to  each  of  the 

1  The  student  may  find  it  easier  to 
manage  a  tadpole  than  a  frog.  The 
following  experiment  showing  the  cir- 
culation of  the  blood  in  the  tail  of 
a  tadpole  is  taken  from  Peabody's 
Laboratory  Exercises  in  Anatomy  and 
Physiology,  p.  56. 

Cut  a  hole  a  half  inch  square  near  the  end  of  a  piece  of  thin  board  three 
inches  long  and  one  inch  wride ;  glue  a  thin  cover  glass  over  the  hole. 
Cover  the  rest  of  the  piece  of  wood  with  absorbent  cotton  soaked  in  water. 
Lay  a  live  tadpole  on  the  cotton,  placing  the  tip  of  the  tail  on  the  cover 
glass.  Lay  a  cover  glass  on  top  of  the  tail,  and  fasten  cheese  cloth  over 
the  animal  to  keep  it  in  place.  Keep  a  plentiful  supply  of  moisture  about 
the  animal  by  allowing  the  end  of  the  strip  of  cloth  to  dip  into  a  dish  of 
water.  Examine  the  tip  of  the  tail  with  a  compound  microscope  magni- 
fying about  seventy-five  diameters. 


FIG.  94. 

Showing  how  the  circulation  of  blood 
in  the  web  of  a  frog's  foot  looks  as 
seen  under  the  microscope. 


THE   CIRCULATION   OF   THE   BLOOD  153 

two  longest  toes,  but  not  tight  enough   to  stop   the  circulation  or 
hurt  the  frog. 

Fasten  the  frog  upon  the  board  in  such  a  way  that  the  foot  will 
just  come  over  the  glass  slide.  Pull  carefully  the  thread  tied  to  the 
toes,  so  as  to  spread  out  the  web  over  the  glass.  Fasten  the  threads 
by  drawing  them  into  slits  cut  in  the  sides  of  the  board.  The  board 
should  now  be  fixed  by  elastic  bands,  or  by  any  other  convenient 
means,  upon  the  stage  of  the  microscope.  The  web  should  be  occa- 
sionally moistened  with  water.  Care  should  be  taken  not  to  occasion 
any  pain  to  the  frog.  The  circulation  of  blood  thus  shown  is  a 
wonderful  sight,  and  never  to  be  forgotten. 

211.  The  Beat,  or  Impulse,  of  the  Heart.     If  the  hand 
be  laid  flat  over  the  chest  wall  on  the  left  side,  a  peculiar 
throbbing  will  be  felt.    This  throbbing  movement  is  known 
as  the  beat,  or  impulse,  of  the  heart.     It  is  due  to  the  hard, 
tense  part  of  the  ventricles  coming  in  contact  with  the 
chest  wall  at  the  moment  when  the  hardening  of  the  ven- 
tricles takes  place.     The  heart  beats  are  unusually  strong 
during  active  bodily  exertion  and  under  mental  excitement. 

212.  The  Sounds  of  the   Heart.     If   we  place  our  ear 
against  a  friend's  chest,  over  the  region  of  the  heart,  we 
hear  two   distinct   sounds.     These  sounds   may  be  fairly 
imitated  by  pronouncing  the  syllables  lub,  dup.     The  first 
is  a  dull,  muffled  sound,  known  as  the  "first  sound,"  fol- 
lowed at  once  by  a  shorter  and  sharper  sound,  known  as 
the  " second  sound"  of  the  heart.1 

213.  The  Pulse.     If  the  finger  be  placed  over  an  artery 
which  lies  near  the  surface  of  the  body,   like  the  radial 

1  The  precise  cause  of  the  first  sound  is  not  certainly  known,  but  the 
second  sound  is,  without  doubt,  caused  by  the  tension  of  the  semilunar 
valves  of  the  pulmonary  artery  and  the  aorta  at  the  moment  when  the 
contraction  of  the  ventricles  is  completed.  If  these  valves  are  diseased 
and  do  not  shut  properly,  a  blowing  sound  or  murmur  will  be  produced. 
Thus,  by  listening  to  the  sounds  of  the  heart  a  doctor  may  be  able  to  tell 
whether  the  valves  are  out  of  order. 


154 


OUR   BODIES  AND   HOW  WE   LIVE 


artery,  for  instance,  near  the  wrist, 
or  the  temporal  artery,  just  over 
the  temples,  a  slight  throbbing 
pressure  on  the  finger  will  be  felt. 
This  pressure,  which  comes  and 
goes  at  regular  intervals,  corre- 
sponds to  the  beats  of  the  heart. 
It  is  called  the  pulse. 

Let  us  learn  the  reason  for  it. 
When  the  left  ventricle  contracts, 
the  blood  is  forced  into  t"he  arter- 
ies and  their  walls  are  suddenly 
distended.  This  wave  of  disten- 
sion, or  pulse,  can  be  felt  in  all 
the  large  arteries. 

In  a  grown  person  the  pulse  beats 
about  seventy-two  times  a  minute. 
In  children  the  pulse  is  quicker 
than  in  adults.  In  old  age  the 
pulse  is  slower  than  in  adult  life. 

By  feeling  the  pulse  with  a  skilled 
touch  it  can  be  told  whether  the 
heart  beat  is  too  fast  or  too  slow, 
strong  or  weak,  regular  or  irregular. 
Thus,  the  pulse  is  a  most  important 
~  .-  T  *  •  guide  to  the  doctor,  for  it  may  tell 

FIG.  95.    The  Infenor  Vena  fc><  ' 

Cava  and  the  Superior  him  many  things  about  the  condi- 

Vena   Cava,  with   their  tion  of  his  patient. 
Connecting  Veins. 

A,  inferior  vena  cava,  cut  off  just  above  the  hepatic  veins :  £,  superior  vena  cava,  cut 
off  just  below  the  junction  of  the  innominate  veins ;  C,  right  and  left  innominate 
veins ;  Z),  left  internal  jugular  vein.  The  veins,  known  as  azygos,  with  some  of 
their  main  branches,  are  shown.  These  veins  connect  the  superior  vena  cava  and 
the  inferior  vena  cava. 


THE   CIRCULATION   OF  THE   BLOOD  155 

Experiment  45.     To  illustrate  the  effect  of  muscular  exercise  in 
quickening  the  pulse.     Run  a  short  distance.     Count  the  pulse  both 
before    and    after.     Note    the   effect   of 
running  upon  the  rate. 

Experiment  46.  To  hear  the  sounds 
of  the  heart.  Borrow  a  stethoscope  from 
some 'physician  and  listen  to  the  heart 
beat  of  a  friend.  Note  the  sounds  of 
your  own  heart  in  the  same  way. 

Experiment  47.  To  find  the  pulse. 
Grasp  the  wrist  of  a  friend,  pressing 
with  three  fingers  over  the  artery,  and- 
note  the  pulse.  Press  three  fingers  over 
the  radius  in  your  own  wrist,  and  note 
the  pulse. 

Count  by  a  watch  the  rate  of  your 
pulse  per  minute,  and  do  the  same  with 
a  friend's  pulse.  Compare  its  character 
with  your  own. 

214.  How  Alcohol  gets  into  the 
Blood.  Alcohol  passes  into  the 
blood  by  two  distinct  routes.  When 
an  alcoholic  liquor  is  taken  into  the 
stomach,  some  of  it  at  once  soaks 
through  the  coats  of  the  tiny  blood 
vessels  with  which  the  inner  wall 
of  the  stomach  is  covered,  and  is 
carried  into  the  blood  current  by 
the  portal  circulation. 

Alcohol  is  also  taken  Up  by  the       FlG-  9°"-     The  Internal,  or 
,  ,  ,    .  , .    ,    ,        .,  Long  Saphenous,  Vein 

lacteals,  and  is  emptied  by  them        of  t*e  L;ft  Leg 
into  the  blood  current  by  way  of 

the  thoracic  duct.    Now,  although  alcohol  goes  to  the  heart 
to  be  sent  to  every  part  of  the  body  in  this  roundabout  way 


I56 


OUR   BODIES   AND   HOW   WE   LIVE 


through  the  liver,  it  takes  only  a  moment  or  two  for  it  to 
get  into  the  main  blood  stream. 

A  glass  of  strong  drink  soon  "goes  to  the  head,"  as 
many  people  know,  showing  that  its  effects  are  rapidly 
produced  in  the  cells  of  the  brain.  The  rapidity  of  this 
absorption  depends  upon  the  kind  of 
liquor  and  whether  the  stomach  is  empty 
or  full. 

215.  The  Effect  of  Alcohol  upon  the 
Blood  Vessels.  The  effect  of  alcohol  on 
the  circulation  is  shown  by  its  action 
on  the  nervous  system.  The  muscular 
walls  of  the  arteries  are  made  larger  or 
smaller  by  means  of  tiny  nerves  which 
regulate  their  size. 

Even  a  moderate  amount  of  alcohol 
disorders  or  paralyzes   for  a   time  the 
action    of   those  nerves  which   control 
the  blood  vessels.     The  muscular  fibers 
of  the  arteries  are  relaxed,  the  blood 
distends   them,   and    the    skin   appears 
redder  and  seems  warmer  than  before 
the    alcohol   was    taken.     This  feeling 
of  warmth   is  due  to  the  heat  that  is 
FIG.  97.    The  Femora]  forced  to  the  surface  of  the  body  by  the 
Leg"    blood.     This  also  explains  the  flushed 
face  and  warm  glow  which  so  often  mark  the  appearance 
of  moderate  drinkers. 

216.  Further  Effect  of  Alcohol  upon  the  Blood  Vessels. 
Under  the  influence  of  alcohol,  the  walls  of  the  blood  ves- 
sels, especially  the  capillaries,  after  a  time  become  perma- 
nently dilated.  This  chronic  enlargement  of  the  arterial 


THE   CIRCULATION   OF   THE   BLOOD 


157 


twigs  is  often  seen  in  the  red-streaked  nose,  the  red  or 
purplish  face,  and  the  bloodshot  eyes  of  those  who  have 
indulged  in  strong  drink  for  a  long  time. 

The  continued  use  of  alcoholic  beverages  may  gradually 
bring  about  a  change  in  the  muscular  walls  of  the  arteries. 
In  some  cases  there  is  an  undue  deposit  of  fat  cells  and  other 
morbid  products.  The 
weakened  and  stiffened 
arterial  walls  now  gradu- 
ally lose  their  elasticity 
so  that  they  are  less  able 
to  do  their  part  in  the  cir- 
culation of  the  blood.  At 
last  the  walls  of  the  ar- 
teries become  weakened, 
especially  in  the  arteries 
of  the  brain.  Owing  to 
some  unusual  strain  of 
work,  or  through  mental 
excitement,  the  walls  of 
the  enfeebled  blood  ves- 
sels of  the  brain  may 
burst  and  cause  death 
from  apoplexy.1 

217.  Effect  of  Alcohol  upon  the  Structure  of  the  Heart. 
The  long-continued  use  of  strong  drink  may  produce 

1  The  primary  effects  of  a  moderate  dose  of  diluted  alcohol,  as  a  glass  of 
whisky  and  water,  on  one  unaccustomed  to  it,  are  to  cause  dilation  of  the 
blood  vessels  of  the  skin,  indicated  by  the  flushed  face,  a  more  rapid  beat  of 
the  heart,  and  nervous  excitement  exhibited  by  talkativeness. 

Blood  containing  two  and  one-half  parts  to  one  thousand  of  absolute 
alcohol  almost  invariably  diminishes  within  a  minute  the  work  done  by  the 
heart.  —  H.  NEWELL  MARTIN,  M.D. 


FIG. 


18.     Arteries  and  their  Branches 
at  the  Base  of  the  Brain. 


I58 


OUR  BODIES   AND   HOW  WE   LIVE 


important  changes  in  the  structure  of  the  heart.  As  with 
the  walls  of  the  arteries,  so  with  the  heart :  the  prolonged 
use  of  alcohol  may  cause  a  deposit  of  fatty 
tissue  in  place  of  the  muscular  fibers. 

This  diseased  condition,  known  as  "  fatty 
degeneration,"  may  seriously  interfere  with 
the  heart's  power  of  contraction.  The  walls 
may  become  much  thicker  and  the  ventricles 
smaller  from  this  deposit  of  fat,  and  thus 
the  overtired  organ  may  fail  in  its  efforts 
to  pump  forward  the  blood  which  rushes  in 
from  the  auricles. 

Alcoholic  excess  may  also  cause  an  over- 
growth of  adipose  tissue  upon  the  surface 
of  the  heart  which  may  seriously  interfere 
\\  I  i'W  I !         with  the  normal  cardiac  action. 

Again,  the  ventricles  may  become  much 
too  large,  and  from  lack  of  proper  elasticity 
may  be  unable  to  pump  forward  the  blood. 
All  these  conditions  are  apt  to  cause  the 
valves  to  lose  their  suppleness,  and  may 
cause  death  by  what  is  known  as  sudden 
heart  failure. 

218.  Effect  of  Tobacco  upon  the  Heart. 
The  nicotine  of  tobacco  acts  to  partially 
paralyze  the  nerves  that  control  the  heart's 
FIG.  99.   Artery  in  action.     Under    its    influence    the    move- 
the  Front  of  the  ments  of  tne  neart  are  irregular,  now  feeble 

Right  Leg. 

and  fluttering,  now  thumping  with  appar- 
ently much  force.  Frequently  there  is  severe  pain  about 
the  heart,  often  dizziness  with  gasping  breath,  extreme 
pallor,  and  fainting. 


THE   CIRCULATION    OF   THE    BLOOD  159 

While  tobacco  may  cause  a  more  or  less  injurious  effect 
upon  other  organs  of  the  body,  it  is  upon  the  heart  that  it 
may  work  its  most  serious  wrong.  Upon  this  most  impor- 
tant organ  its  effect  is  often  to  depress  and  paralyze. 
Especially  does  this  apply  to  the  young,  whose  bodies  are 
not  yet  knit  into  the  vigor  of  manhood. 

219.  Heart  Disease  caused  by  Tobacco.  There  are  few 
conditions  more  distressing  than  the  suffering  produced  by 
a  palpitating  heart.  It  is  claimed  by  medical  men  that 
about  one  in  every  four  tobacco  users  is  subject,  in  some 
degree,  to  this  disturbance.  Test  examinations  of  a  large 
number  of  boys  who  had  used  cigarettes  showed  that  only 
a  very  small  percentage  escaped  cardiac  trouble. 

The  condition  of  the  pulse  is  a  guide  to  this  state  of  the 
heart.  In  this  the  physician  reads  plainly  the  existence 
of  the  "  tobacco  heart,"  an  affection  clearly  recognized  by 
the  medical  profession. 

Many  of  the  young  men  who  made  application  to  enlist 
during  our  war  with  Spain,  in  1898,  were  rejected  because 
the  physical  examination  revealed  a  tobacco  heart. 

Of  older  tobacco  users  there  are  very  few  but  have  some 
warning  of  the  effects  of  overindulgence  in  this  narcotic. 
Generally  they  suffer  more  or  less  from  the  tobacco  heart, 
and  if  the  nervous  system  or  the  heart  be  naturally  feeble, 
they  suffer  all  the  more  speedily  and  intensely.1 

1  The  irregularity  in  the  heart's  action,  which  tobacco  causes,  is  one  of 
its  most  conspicuous  effects.  Candidates,  who  are  annually  rejected  for 
cardiac  disturbances,  have  subsequently  admitted  the  use  of  tobacco ;  the 
annual  physical  examination  of  cadets  reveals  a  large  number  of  irritable 
hearts  —  tobacco  hearts  —  among  boys.  —  Surgeon  General  U.  S.  Navy. 

Tobacco,  and  especially  cigarettes,  being  a  depressant  upon  the  heart, 
should  be  positively  forbidden.  —  J.  M.  KEATING,  M.D.,  on  "  Physical 
Development,"  in  Cyclopcedia  of  the  Diseases  of  Children. 


160  OUR   BODIES  AND    HOW   WE   LIVE 


QUESTIONS  ON  THE  TEXT 

I.  What  are  the  two  general  uses  of  the  blood?     2.  State  in  a 
general  way  where  the  blood  vessels  are  found.     3.  Give  some  of  the 
properties  of  blood.     4.  Of  what  does  blood  consist,  and  why  does 
it  look  red?     5.  What  simple  experiment  will  illustrate  in  a  general 
way  why  the  blood  seems  uniformly  red  ?     6.  Describe  the  red  cor- 
puscles.    7.  Of  what  use  are  the  red  corpuscles  ?     8.  Describe  the 
white  corpuscles.      9.   State  briefly  the  use  of  the  white  corpuscles. 
10.  How  does  blood  look  when  examined  with  the  microscope  ? 

II.  What  happens  if  blood  is  allowed  to  stand  for  a  short  time? 
12.  What  is  meant  by  the  coagulation  of  the  blood  ?     13.   Describe 
the  serum  of  the  blood.     14.  Of  what  is  the  clot  composed  ?     15.  Why 
is  the  clotting  of  blood  important  ?     16.   Describe  briefly  the  apparatus 
concerned  in  the  circulation  of  blood.     17.   How  may  the  blood  cir- 
culation be  compared  to  the  water  service  of  a  city?     18.  Describe 
the  heart.     19.  What  is  the  pericardium  ?     20.   In  what  simple  way 
may  the  position  of  the  pericardium  be  shown  ? 

21.  Describe  the  chambers,  or  cavities,  of  the  heart.  22.  What  are 
the  valves  of  the  heart?  23.  Describe  the  action  of  the  various 
valves.  24.  What  can  be  said  of  the  work  done  by  the  heart? 
25.  What  is  the  aorta?  26.  Describe  the  pulmonary  veins.  27.  Describe 
the  pulmonary  artery.  28.  What  are  the  two  largest  veins  of  the 
body,  and  what  is  their  action?  29.  Mention  some  of  the  main 
branches  of  the  aorta.  30.  What  are  veins? 

31.  What  simple  experiment  will  illustrate  the  action  of  the  veins? 
32.  What  are  capillaries  ?  33.  What  interchange  takes  place  between 
the  blood  and  the  lymph  ?  34.  Into  what  two  parts  may  the  course 
of  the  circulation  be  subdivided  ?  35.  Describe  the  pulmo'nary  circu- 
lation. 36.  Describe  the  systemic  circulation.  37.  What  is  meant 
by  the  portal  circulation  ?  38.  What  is  the  beat,  or  impulse,  of  the 
heart?  39.  What  are  the  two  sounds  of  the  heart?  40.  What  is 
the  pulse,  and  what  may  it  indicate  to  the  doctor? 

41.  How  does  alcohol  get  into  the  blood?  42.  What  is  the  effect 
of  alcohol  upon  the  blood  vessels?  43.  What  is  the  effect  of  alco- 
holic excess  upon  the  heart  ?  44.  How  does  tobacco  affect  the  heart? 
45.  Describe  the  so-called  "  tobacco  heart." 


CHAPTER  VIII 
BREATHING 

220.  The  Act  of  Breathing.    Night  and  day,  without  one 
minute's  rest,  from  the  first  to  the  last  moment  of  our 
lives,  we  are  breathing.     Most  of  the  time  we  do  not  think 
anything  about  it.     We  eat,  talk,  work,  and  sleep  ;  and  all 
this  time  our  breathing  goes  quietly  on.     We  can  hold  our 
breath  for  a  short  time,  yet  after  a  few  seconds  we  begin 
to  feel  uncomfortable. 

221.  The  Object  of  Breathing.     In    studying   food   and 
blood,  we  have  learned  that  without  food  and  air  the  burn- 
ing, or  oxidation,  which  is  slowly  going  on  in  our  bodies 
all  the  time,  would  soon  flag,  and  life  would  come  to  an  end. 

We  have  learned  that  the  dark  blood  is  sent  to  the  lungs 
from  the  right  ventricle  and  is  returned  to  the  left  auricle 
as  blood  of  a  bright  red  color.  The  blood  has  got  rid  of 
part  of  its  waste  matter,  and  has  taken  up  oxygen. 

Hence,  in  breathing  we  have  two  objects  in  view:  first, 
to  give  a  fresh  supply  of  oxygen  to  the  blood  ;  second,  to 
get  rid  of  carbon  dioxide  and  other  waste  matter  taken  up 
from  the  tissues  and  brought  to  the  lungs  by  the  blood. 

222.  The  Air  Passages.    The  air  is  drawn  into  the  lungs 
through  the  mouth,  the  nostrils,  and  the  windpipe. 

The  nostrils  are  really  the  passageways  for  the  air,  and 
warm  it  somewhat  before  it  passes  into  the  windpipe,  or 
trachea,  on  its  way  to  the  lungs. 

161 


162 


OUR   BODIES   AND    HOW  WE    LIVE 


The  windpipe  is  a  tube  about  four  inches  long,  which 
is  protected  on  the  front  and  sides  by  stout  rings  of 
cartilage.  But  for  these  rings  the  windpipe  would  close 
with  the  slightest  pressure  and  cut  off  our  breath. 


FIG.  100.     Relative  Position  of  the  Lungs,  the  Heart,  and  Some  of 
the  Great  Vessels  belonging  to  the  Latter. 

A,  left  ventricla ;  B,  right  ventricle  ;  C,  left  auricle  ;  D,  right  auricle ;  E,  superior 
vena  cava ;  f,  pulmonary  artery  ;  G,  aorta ;  //,  arch  of  the  aorta ;  K,  innomi- 
nate artery ;  L,  right  common  carotid  artery ;  Af,  right  subclavian  artery ; 
N,  thyroid  cartilage  forming  upper  portion  of  the  larynx ;  O,  trachea. 

The  top  of  the  windpipe  is  protected  by  a  trapdoor 
known  as  the  epiglottis.  This  little  door,  as  we  have  learned, 
shuts  tight  when  food  is  swallowed,  and  keeps  the  food  out 
of  the  air  passages  ;  otherwise  the  food  would  go  the  wrong 
way,  and  cut  short  our  breath  (Sec.  153  and  Fig,  69). 


BREATHING 


I63 


The  upper  part  of  the  windpipe  is  a  kind  of  box  called 
the  larynx,  or  organ  of  voice.  In  this  box  are  the  vocal  cords. 
In  some  persons  it  is  very  prominent,  and  the  front  edge 
of  it  is  commonly  called 
"Adam's  apple  "(Figs.  100, 
173,  174,  and  175). 

223.  The  Bronchial 
Tubes.  The  windpipe, 
after  entering  the  chest, 
divides  into  two  branches 
called  bronchi,  one  to  each 
lung.  These  again  divide 
into  smaller  tubes  called 
bronchial  tubes. 

Each  bronchial  tube 
divides  again  into  smaller 
branches,  these  again  into 
smaller,  and  so  on  to  the 
tiniest  twigs  many  times 
smaller  than  the  hairs  of 
our  head. 

The  numberless  bron- 
chial tubes  pass  to  all  parts 

of  the  lungs,  and  end  finally     FIG.  101.     Larynx,  Trachea,  and  the 


Bronchi.     (Front  view.) 

,  epiglottis ;  B,  thyroid  cartilage ;  C,  crico- 
thyroid  membrane,  connecting  with  the 
cricoid  cartilage  below,  all  forming  'the 
larynx ;  D,  rings  of  the  trachea. 


in  clusters  of  short,  blind, 

and   somewhat    dilated 

pouches  called  alveoli. 

Each  of   these    closed, 

dilated  ends  is  divided  into  a  number  of  air  cavities  or 

air  sacs. 

If  we  remember  that  all  these  tubes,  great  and  small, 
are  hollow,  we  may  compare  them  to  a  short  bush  or  tree 


1 64 


OUR  BODIES   AND   HOW  WE   LIVE 


growing  upside  down  in  the  chest,  of  which  the  windpipe 

is  the  trunk,  the  bronchial  tubes  are  the  branches,  and  the 

air  cavities  of  the  lungs  are  the  leaves. 

224.   The  Lungs.     The   lungs   are   two    large,   pinkish, 

spongy  organs,  which  surround  the  heart  and  the  large 

vessels,  and  fill  up 
all  the  rest  of  the 
chest  cavity.  So 
light  and  spongy  is 
their  structure  that 
a  piece  of  a  lung, 
unlike  any  other 
tissue,  will  float  in 
water. 

The  right  lung 
is  the  larger  of  the 
two,  and  has  three 
parts,  or  lobes.  The 


FIG.  102.     The  Lungs,  with  the  Trachea,  Bronchi,    left  lun&   haS 

and  Larger  Bronchial  Tubes  exposed.     (Pos-    two   lobes.       Each 

*'  looe  is   also  made 

A,  division  of  left  bronchus  to  upper  lobe ;  B,  left  branch 

of  the  pulmonary  artery;  C,  left  bronchus;  D,  left  UP  °f  manY  grouPS 

superior  pulmonary  vein  ;  E,  left  inferior  pulmonary  of  Smaller  part  S, 

vein;  P,  left  auricle ;  K,  inferior  vena  cava ;  L,  divis-  11     1    i  K   1                 V> 

ion  of  right  bronchus  to  lower  lobe ;  M,  right  inferior  Cal1    1    loDules>    eac 

pulmonary  vein ;  N,  right  superior  pulmonary  vein;  with  its  little  bron- 

O,  right  branch  of  the  pulmonary  artery ;  P,  division  •,  •    -,        -, 

of  right  bronchus  to  upper  lobe;  R,  left  ventricle;  cniai  tUDC,  air  SaCS, 

S,  right  ventricle.  and  blood  VCSSels. 

The  chest  is  lined  and  each  lung  covered  with  a  smooth, 
delicate  lining,  called  the  pleura.  These  two  surfaces  rub 
against  each  other  when  we  breathe.  This  lining  secretes 
a  fluid  which  keeps  the  parts  always  moist  and  prevents 
their  rubbing  on  one  another. 


BREATHING  165 

225.  How  Nature  protects  the  Air  Passages.  The  inside 
walls  of  the  windpipe  and  bronchial  tubes  are  lined  with 
a  mucous  membrane,  which  secretes  a  thick,  sticky  fluid 
called  "  mucus,"  to  keep  the  passages  moist.  This  mem- 
brane is  covered  with  microscopic,  threadlike  processes 
called  cilia,  so  close  together  that  they  resemble  somewhat 
the  pile  on  velvet.  They  seem  to  wave  to  and  fro,  like  a 
field  of  grain  under  a  gust  of  wind  (Fig.  4). 

The  cilia  always  bend  upwards  and  outwards  towards 
the  mouth  with  considerable  force  and  then  resume  their 
former  position  with  a  very  gentle  movement.  They  sweep 
up  bits  of  dust  and  mucus  which  are  expelled  by  a  sudden 
blast  of  air  which  we  call  coughing.  These  tiny  cilia  are 
simply  the  dusters  which  nature  uses  to  keep  the  air  pas- 
sages neat  and  clean. 

Experiment  48.  The  respiratory  sounds  may  be  heard  fairly  well 
by  applying  the  ear  flat  to  the  chest,  with  only  one  garment  inter- 
posed. Borrow  a  stethoscope  from  a  physician  and  listen  to  the 
respiration  over  the  chest.  Note  the  difference  of  the  sounds  in 
inspiration  and  in  expiration.  Do  not  confuse  the  heart  sounds  with 
those  of  respiration. 

Experiment  49.  Place  a  large  sponge,  which  will  represent  the 
lungs,  in  a  paper  bag  which  justs  fits  it;  this  will  represent  the 
pulmonary  layer  of  the  pleura.  Place  the  sponge  and  paper  bag 
inside  a  second  paper  bag,  which  will  represent  the  parietal  layer 
of  the  pleura.  Join  the  mouths  of  the  two  bags.  The  two  surfaces  of 
the  bags  which  are  now  in  contact  will  represent  the  two  surfaces 
of  the  pleura. 

Experiment  50.  Get  a  sheep's  lungs,  with  the  windpipe  attached. 
Ask  for  the  heart  and  lungs  all  in  one  mass.  Examine  the  windpipe. 
Note  the  horseshoe-shaped  rings  of  cartilage  in  front,  which  serve  to 
keep  it  open.  Put  pieces  of  the  lung  tissue  in  a  basin  of  water  and 
note  that  they  float. 


1 66 


OUR  BODIES   AND   HOW   WE    LIVE 


Experiment  51.  To  show  how  the  lungs  may  be  filled  with  air. 
Take  the  lungs  saved  from  Experiment  50.  Tie  a  glass  tube  six 
inches  long  into  the  larynx.  Attach  a  piece  of  rubber  tubing  to  one 
end  of  the  glass  tube.  Now  inflate  the  lungs  by  blowing  through 
the  rubber  tube  several  times  and  let  them  collapse. 


FIG.  103.     Relative  Position  of  the  Lungs,  the  Heart,  and  Some  of 
the  Great  Vessels  belonging  to  the  Latter.     (Posterior  view.) 

A,  left  common  carotid  artery  ;  B,  external  carotid  artery ;  C,  internal  carotid 
artery  ;  D,  left  jugular  vein  ;  E,  sterno-cleido  muscle ;  F,  right  innominate 
artery  with  branches  to  head  and  arm  -,  G,  left  subclavian  artery  ;  H,  great 
azygos  vein  ;  A",  thoracic  duct. 


BREATHING 


I67 


226.  The  Movements  of  Breathing.  If  we  put  both  hands 
on  the  sides  of  our  own  chest  and  breathe*  in  deeply, 
we  feel  that  the  act  has  carried  the  hands  farther  apart. 
Again,  if  we  put  one  hand  across  the  middle  of  our  chest, 
we  feel  that  it  is  carried  forward  every  time  we  breathe 
in  and  is  returned 
to  its  place  as  we 
breathe  out. 

Again,  if  we 
pass  a  tape  meas- 
ure round  the 
chest  and  draw  it 
tight  when  we 
breathe  out,  we 
find  that  the  tape 
must  be  let  out 
two  or  three  inches 

as  we  breathe  in.        (fT<^\  ^-^^  J         I    (-B 

If  we  breathe  in 
and  out  with  a 
great  deal  of  force, 
the  changes  are  FlG>  I04> 

rr»r.r^    t-nor-1r^/l  Diagram  showing  how,  as  the  ribs  move  upward,  the  ster- 

IIlUl  C     IlldlivcCl.  f  ,  ,  .  .  -    .         . 

num  moves  iorward,  and  increases  the  size  of  the  chest 

HeilCe  there  are       during  inspiration.     The  first  seven  ribs  are  numbered. 
tWO  movements  in        Dotted  lines  indicate  position  in  inspiration.   A  and  B 
indicate  the  extent  of  the  movement. 

breathing,   in  one 

of  which  the  cavity  of  the  chest  is  made  larger  in  all  its 
dimensions.  This  is  when  we  breathe  in  air,  and  it  is 
called  inspiration. 

The  other  movement  is  the  one  by  which  the  chest 
cavity  is  made  smaller.  This  is  when  we  breathe  out  air, 
and  it  is  called  expiration. 


168  OUR   BODIES   AND   HOW   WE    LIVE 

The  movements  by  which  air  is  breathed  in  and  out  of 
the  lungs  make  up  the  act  of  respiration. 

227.  How   we  breathe.     The  cavity  of  the  chest  is  a 
closed,  air-tight  chamber,  whose  only  opening  is  the  wind- 
pipe.    The  pressure  of  the  air  in  the  air  passages  keeps 
the  lungs  stretched  out  so  as  to  fill  this  cavity.      Imagine 
now  such  a  chamber  as  this  to  have  a  kind  of  floor,  capable 

of  moving  up  and  down.  When 
the  floor  moves  down,  the  cav- 
ity will  be  enlarged,  and  the 
pressure  of  the  air  inside  the 
lungs  will  then  cause  them  to 
expand  to  a  greater  extent  to 
fill  up  the  extra  space. 

When  the  floor  is  raised  again, 
the   cavity  will   be   diminished 
and  the  lungs,  being  diminished 
also,  will  give  up  the  extra  air 
FIG.  105.   BLACKBOARD  SKETCH,    which  they  have  taken  in. 

A  Lobule  of  the  Lung.  The   diaphragm    serves    as    a 

A,  an  air  sac ;  B,  an  air  sac  cut  open  ;  kind    of     movable    floor    to    the 

C,  capillary  network  over  an   air  ,            ,-. 

sac;  D,  branch  of  pulmonary  artery;  Ctl'           rig.    I 

£,  branch  of  pulmonary  vein;  F,  These     tWO     movements     are 

bronchial  tube.  r                                     , 

performed  at  regular  intervals 
and  constitute  the  process  of  breathing. 

228.  Inspiration  and  Expiration.    The  cavity  of  the  chest, 
however,  is  enlarged  in  another  way.     The  walls  of  the  chest 
are  formed  by  the  ribs,  which  encircle  it  and  join  the  breast- 
bone in  front.     The  spaces  between  the  ribs  are  filled  with 
a  set  of  strong  muscles  called  the  intercostal  muscles. 

One  set  of  these  intercostal  muscles  contracts,  and  pulls 
up  the  ribs,  which  are  fastened  to  the  backbone  behind  by 


BREATHING 


I69 


a  joint.  When  the  ribs  are  raised,  they  push  out  the  breast- 
bone in  front,  and  thus  the  cavity  of  the  chest  is  enlarged. 
This  enlargement  by  means  of  the  side  walls  takes  place  at 
the  same  time  that  the  diaphragm  descends,  so  that  the 
chest  is  enlarged  in  all  its  dimensions  (Fig.  104). 

An  extra  quantity  of  air  then  rushes  into  the  lungs  and 
we  get  an  inspiration. 

Immediately  following  the  inspiration,  the  diaphragm 
relaxes,  and,  of 
course,  rises ;  and, 
at  the  same  time, 
another  set  of  in- 
tercostal muscles 
begins  to  pull  the 
ribs  and  breastbone 
down. 

These  combined 
movements  dimin- 
ish the  cavity  of  the 
chest,  and  conse- 
quently the  air  is 
driven  out.  This 
makes  an  expiration. 


FIG.  1 06. 


Showing  the  walls  of  air  sacs  with  blood  capillaries 
injected.  The  dark  lines  are  the  capillaries 
magnified  about  30  times.  The  white  spaces 
are  air  sacs  cut  across. 


Experiment  52.  To 
show  how  the  size  of 
the  chest  varies  during 
respiration.  Stand 

erect  with  shoulders  well  thrown  back.  While  breathing  naturally, 
allow  some  friend  to  pass  a  tape  around  the  body  just  under  the  arms, 
bringing  the  ends  of  the  tape  together  across  the  front  of  the  chest. 
Take  the  exact  measure  (Fig.  104). 

Repeat  as  before,  while  taking  a  long,  deep  inspiration.     Hold  the 
breath  and  measure  as  before.    Note  the  difference  in  measurement. 


OUR   BODIES   AND   HOW  WE    LIVE 


229.  The  Air  we  breathe.  The  air  that  we  breathe  is 
chiefly  a  mixture  of  two  gases,  oxygen  and  nitrogen,  in  the 
proportion  of  one  part  of  the  former  to  four  of  the  latter. 

Oxygen  is  the  active  gas,  the  life-giving  principle  of 
nature.  It  has  been  well  named  "  the  great  supporter  of 
animal  life." 

Nitrogen  is  mixed  with  it,  otherwise  the  oxygen  would 
be  too  strong  for  us,  and  would  burn  us  up  too  fast.  In 

short,  nature  kindly 
tempers  with  nitro- 
gen the  air  which  we 
breathe. 

230.  How  the  Air 
is  changed  in  Breath- 
ing. If  we  examine 
the  air  before  it  en- 
ters the  lungs,  and 
again  after  it  has 
passed  through  them, 
we  shall  find  that, 

FIG.  107.     A  Portion  of  a  Child's  Lung.         while  the  bulk  is  al- 
Lobules  of  various  sizes  are  well  shown.  most    exactly    the 

same,  the  composi- 
tion has  been  changed.  It  has  left  behind  about  one 
quarter  of  its  oxygen,  and  has  taken  in  exchange  for  it 
nearly  the  same  quantity  of  carbon  dioxide,  a  gas  which  is 
destructive  to  life  when  present  in  large  amounts.  Carbon 
dioxide  is  not  poisonous  in  itself,  but  its  presence  excludes 
the  life-giving  oxygen. 

About  thirty  cubic  inches  of  air  pass  in  and  out  of  the 
lungs  with  every  breath,  and  more  than  three  hundred 
cubic  feet  every  twenty-four  hours. 


BREATHING 


231.  Other  Changes  in  the  Air  we  breathe.  The  air,  as 
it  leaves  the  lungs,  is  saturated  with  watery  vapor.  This  is 
seen  when  we  breathe  on  the  bright  steel  blade  of  a  pocket- 
knife,  a  mirror,  or  any  cold,  polished  surface.  As  we  all 
know,  the  surface  becomes  covered  with  a  thin  film,  or 
minute  drops  of  water.  In  cold 
weather  this  moisture  becomes 
visible  with  each  expiration. 

Air  as  it  leaves  the  lungs  is 
warmer  than  the  surrounding  air. 
It  is  generally  about  98°  F.  For 
this  reaso'n,  on  a  cold  day,  when 
our  breath  passes  off  as  a  cloud 
of  steam,  we  blow  on  our  fingers 
to  warm  them. 

The  air  breathed  out  of  the 
lungs  also  contains  a  small 
amount  of  decaying  animal  mat- 
ter. Everybody  knows  the  un- 
pleasant odor  of  the  air  in  rooms 
in  which  many  persons  have  been 
closely  shut  up. 


FIG.  1 08. 

Showing  the  structure  of  a  lobule 
of  the  lung.  The  lobule  has  been 
injected  with  mercury,afterwards 
dried  and  cut  open.  A  large 
bronchial  tube  with  its  various 
branches  is  well  shown. 


Experiment  53.  To  show  that  the 
air  we  expire  is  warm  and  moist. 
Breathe  on  a  thermometer  for  a  few 
minutes.  The  mercury  will  rise  rapidly. 

Breathe  on  a  mirror,  a  knife  blade,  or  any  polished  metallic 
surface,  and  note  the  deposit  of  moisture. 

Experiment  54.  To  show  that  the  expired  air  contains  carbon 
dioxide.  Put  a  glass  tube  into  a  glass  of  clear  limewater  and  blow 
through  the  tube.  The  liquid  will  soon  become  milky,  because  the 
carbon  dioxide  of  the  expired  air  unites  with  the  lime  held  in  solu- 
tion and  forms  the  white,  solid  carbonate  of  lime. 


OUR  BODIES  AND   HOW  WE   LIVE 

Experiment  55.  Pass  a  tube  through  a  cork  ;  fix  the  cork  tightly 
into  a  dry,  wide-mouthed  bottle.  Breathe  in  and  out  of  the  bottle 
several  times  in  succession  until  a  feeling  of  suffocation  is  felt.  The 
bottle  will  become  moist  and  warm. 

If,  holding  the  bottle  upside  down,  we  take  the  cork  out  and  pass 
a  lighted  splinter  of  wood  within,  the  light  will  be  at  once  put  out, 
for  the  oxygen  will  have  almost  entirely  disappeared,  and  it  is  replaced, 
by  carbon  dioxide. 

232.  The  Diffusion  of  Gases.  Let  us  try  to  understand 
how  this  exchange  of  gases  takes  place  between  the  air 
and  the  blood. 

Experiments  carried  on  outside  of  the  body  prove  that 
gases  can  pass  through  delicate  membranes.  If  a  bladder 
is  filled  with  oxygen  and  then  hung  in  a  bottle  filled  with 
carbon  dioxide,  the  two  gases  will  mix  with  each  other. 
The  oxygen  will  pass  out  through  the 
thin  membrane,  and  the  carbon  diox- 
ide will  pass  in.  This  is  in  accordance 
with  a  well-known  law  of  physical 
science  and  is  known  as  the  diffusion 

FIG.  109.     Diagrammatic   of  Sases- 

View  of  an  Air  Sac.  233.  Exchange  of  Gases  between  the 
A,  epithelial  lining  wall;  Blood  and  the  Air.  An  exchange  of 

B.  partition  between  two  ,,  ,  ,, 

adjacent  sacs,  in  which  gases  really  takes  place  in  the  tissues 
run  capillaries;  c,  fibers  of  the  body   every  moment    of   our 

of  elastic  tissue.  ..  1          .  . 

lives.     The  blood  and  the  air  cavities 

of  the  lungs  are  separated  from  each  other  only  by  the 
thin  and  delicate  epithelial  lining  wall  of  the  air  sacs  and 
by  the  walls  of  the  capillaries. 

Blood  with  oxygen  and  carbon  dioxide  is  on  one  side  of 
this  thin,  moist  membrane,  and  the  air  in  the  air  sacs  con- 
taining the  same  two  gases  is  on  the  other  side.  The 
proportion  of  carbon  dioxide  in  the  blood  is  greater  than 


BREATHING 


173 


that  in  the  air  sacs,  and  the  proportion  of  oxygen  in  the 
blood  is  less  than  that  in  the  air  sacs. 

A  diffusion  of  the  gases  takes  place. 

The  blood,  by  this  act  of  breathing,  gains  oxygen  and 
loses  carbon  dioxide. 

The  air  sacs  lose  oxygen 
and  gain  carbon  dioxide. 

234.  Respiration  in  all 
of  the  Tissues.  The  blood 
thus  freighted  with  oxy- 
gen travels  to  the  left  side 
of  the  heart,  is  pumped 
out  through  the  aorta,  and 
whirled  away  to  the  tissues  FIG  IIQ  BLACKBOARD  SKETCH. 
in  every  part  of  the  body.  Diagram  showing  Capillary  Network  of 

The  tissues  are  most  eager        the  Air  Sacs  and  Origin  of  the  Pul- 
tO  Combine  with   the   life-        monary  Veins. 

giving  oxygen  and  to  give  A>  S™1\  branch  of  Pulmo"f  y  ***y  ;  *»  twi§* 

&        J  &  of  pulmonary  artery  ;  C,  capillary  network 


around  the  walls  of  the  air  sacs;  A  branches 
°^  network  converging  to  form  the  veinlets 
of  the  pulmonary  veins. 


Up   Carbon  dioxide   tO    the 
Klnnrl 

The  oxygen  given  off 
to  the  tissues  by  the  arterial  blood  in  the  capillaries  may 
not  be  used  to  produce  oxidation  at  once,  but  may  be  stored 
up  for  future  use  in  muscular  and  other  tissues. 

During  severe  exercise  the  amount  of  carbon  dioxide 
breathed  out  may  often  exceed  the  whole  amount  of  oxy- 
gen taken  in  by  the  lungs  during  the  time  of  action.  In 
other  words,  during  severe  exercise  the  muscles  may  use 
up  the  oxygen  which  has  been  stored  in  their  tissues  during 
periods  of  rest. 

235.  Impurities  in  the  Air.  There  are  many  things 
which  may  make  the  air  we  breathe  unwholesome.  The 


OUR   BODIES   AND   HOW   WE    LIVE 

poisoned  air  due  to  cesspools,  drains,  and  sewers  is  a  fre- 
quent source  of  disease.  Sewer  gas,  the  foul  air  from 
chemical  works,  bone  and  soap  factories,  and  many  other 
manufacturing  places,  may  be  hurtful  to  health. 

Certain  occupations  may  shorten  life  by  exposure  to  air 
laden  with  impurities.  Thus,  there  is  the  "  miner's  con- 
sumption," or  "black  lung,"  due  to  the  dust  which  is 
breathed  into  the  lungs,  and  acts  like  so  many  little  splin- 
ters in  the  delicate  air  cells.  Refiners  of  mercury  work 
in  a  deadly  atmosphere.  Those  who  work  on  steel,  emery, 
cutlery,  pottery,  etc.,  also  suffer  from  the  irritating  dust 
floating  in  the  air. 

Other  impurities  are  highly  injurious  to  the  lungs,  as  the 
dust  in  match  factories,  white-lead  works,  and  copper  and 
brass  foundries.  In  fact,  among  some  classes  of  factory 
workers  the  rate  of  mortality  is  higher  than  among  firemen, 
freight  brakemen,  and  men  in  other  pursuits  known  to 
involve  great  risk  of  life. 

236.  How  Bacteria  may  be  carried  in  the  Air.  Many 
kinds  of  bacteria  are  carried  in  the  air.  Some  of  these 
germs  may  grow  and  produce  disease  if  taken  into  the  body 
through  the  air  passages,  in  the  food,  or  in  drinking  water. 
Thus,  we  shall  learn  that  the  germs  of  certain  infectious 
diseases  may  be  carried  in  the  air  and  produce  similar  diseases 
in  persons  who  may  become  infected  by  them. 

The  germs  of  disease  after  floating  about  in  the  air  for  a 
time  may  settle  with  the  dust.  If  an  infected  room  is  not 
properly  swept  and  dusted,  there  is  an  ever-present  danger 
of  spreading  contagious  diseases.  Hence  a  sick  room  should 
be  kept  rigidly  clean  and  furnished  with  a  constant  supply 
of  pure,  fresh  air.  It  is  well  knowa  that  the  dust  in  the 
streets  of  large  towns  contains  the  germs  of  disease. 


BREATHING 


175 


237.  The  Dangers  from  Pulmonary  Infection.  There  is 
an  infectious  disease  called  tuberculosis  of  the  lungs,  but  com- 
monly known  as  consumption.  It  is  caused  by  the  growth 
within  the  lungs  of  a  disease  germ  called  bacillus  tuberculosis. 

The  sputum  of  a 
consumptive  swarms 
with  these  bacteria. 
This  infected  matter, 
falling  upon  the  street 
or  about  a  room,  soon 
dries  and  may  become 
mixed  with  the  com- 
mon dust  floating 
through  the  air.  It 
may  retain  its  vitality 
for  a  long  time  as  a 
part  of  the  dust  of 
damp,  filthy,  or  over- 
crowded  houses. 

.         A  minute  portion  of  sputum  from  a  case  of  phthisis, 

1  niS  ClUSt  When  in-  or  consumption  of  the  lungs,  magnified  1000  diam- 
eters. These  bacilli  are  rod-shaped  bacteria, 
stained  to  show  black.  The  black  spots  in  the 
figure  are  merely  the  debris  in  the  sputum,  also 
stained  so  that  they  look  black. 


FIG.  in.     Bacillus  Tuberculosis. 


haled  often  finds  in 
the  body  a  congenial 
soil  upon  which  the 
seeds  of  this  dread  disease  may  be  transplanted. 

238.  Ventilation.  The  best  way  to  rid  our  rooms  and 
premises  of  impure  air  is  by  some  suitable  system  of  venti- 
lation, —  that  is,  some  practical  and  efficient  plan  to  keep 
the  air  pure  and  wholesome  without  making  it  too  cold.  If 
we  do  our  best,  however,  we  cannot  keep  the  air  of  our  living 
rooms  as  pure  as  the  outside  air  ;  for,  as  we  have  seen, 
every  person  in  the  room,  with  every  breath,  is  consuming 
the  oxygen  and  imparting  carbon  dioxide  to  the  air. 


176  OUR  BODIES  AND   HOW   WE   LIVE 

239.  How  to  ventilate.  An  open  fireplace  is  a  safe, 
healthy,  but  not  economical  means  of  heating  and  venti- 
lating a  room.  Stoves  in  a  room  soon  dry  the  air,  unless 
fresh  air  from  outside  is  constantly  supplied.  When  rooms 
are  warmed  by  heated  air  from  furnaces,  the  warm  air  should 
enter  through  registers  in  or  near  the  floor,  on  one  side  of 
the  room  ;  and  impure  air  should  escape  through  outlets  in 
or  near  the  ceiling,  on  the  other  side. 

Children  should  be  trained  from  infancy  to  sleep  with  a 
window  partly  open  for  the  greater  part  of  the  year.  Adult 
people  in  vigorous  health  should  gradually  learn  to  do  the 
same.  Even  in  the  coldest  weather  some  plan  of  venti- 
lation for  the  living  rooms,  but  especially  for  the  sleeping 
rooms,  should  be  provided.  Draughts  must  be  avoided. 

Any  simple  apparatus  to  let  in  fresh  air  will  answer  every 
purpose.  Raise  the  window  a  few  inches  and  put  a  piece 
of  board  under  the  lower  sash.  Pure  air  will  enter  where 
the  two  sashes  overlap.1 

1  Above  all  things,  avoid  sitting,  standing,  or  lying  in  a  cool,  breezy  place 
when  you  are  warm  from  active  exercise.  This  is  a  sure  way  to  catch  cold. 
Do  not  stand  by  open  windows  or  open  doors  when  the  air  of  the  house  is 
warmer  than  that  outside.  You  are  subjected  to  a  strong  draught,  which 
is  sure  to  result  in  a  cold.  Do  not  stop  to  talk  in  the  doorway  when 
parting  from  a  friend. 

Do  not  throw  off  your  wraps  too  suddenly  when  coming  in  warm  with 
exercise. 

Do  not  talk  much  when  walking  in  the  cold,  frosty  air,  but  keep  the 
mouth  closed,  that  the  air  may  be  warmed  by  the  nostrils. 

Avoid  very  hot  rooms  with  the  moisture  all  dried  out  of  the  air.  Change 
the  air  of  your  room  every  hour.  An  hour  is  long  enough  to  remain  in  one 
position  or  in  one  room  without  change. 

Never  sit,  eat,  or  sleep  in  a  north  room  if  you  can  help  it.  The  north 
side  of  the  house  belongs  to  the  refrigerator  and  the  storeroom.  Let  the 
sun  shine  into  all  your  rooms  as  much  as  possible.  You  had  better  have 
faded  carpets  than  faded  faces.  —  DR.  MARY  J.  STUDLEY,  in  What  Our  Girls 
Ought  to  Know. 


BREATHING 

240.  Ventilation  of  Schoolrooms.  Special  pains  must  be 
taken  to  ventilate  schoolrooms.  Pupils  are  sure  to  become 
listless,  uneasy,  dull,  and  sleepy  when  the  air  is  not  whole- 
some. Children  may  be  comfortable  in  a  well-aired  room 
at  66°  F.,  but  it  is  very  easy  to  let  the  temperature  run  up 
to  80°,  or  even  above,  before  it  is  noticed. 

Whatever  apparatus  for  ventilation  may  be  used,  the 
doors  and  windows  should  be  opened  before  and  after 
each  session  and  at  recess. 


FIG.  112. 

Two  petri  dishes:  one,  A,  exposed  to  the  air  before,  and  the  other,  B, 
exposed  after,  a  class  had  occupied  a  recitation  room.  Plate  A  shows 
few  bacteria,  while  plate  B  contains  large  numbers. 

The  air  of  the  schoolroom  should  be  changed  as  often 
as  once  every  hour.  The  pupils  meanwhile  should  engage 
in  active  gymnastic  exercises  to  prevent  taking  cold.  When 
this  is  done  in  cold  weather,  the  heat  should  be  turned  on 
and  the  fresh,  cold  air  warmed  as  quickly  as  possible.1 

1  School  children  sitting  at  their  desks,  clerks  bending  over  their  ledgers, 
seamstresses  at  work  with  the  needle  or  the  sewing  machine,  stenographers, 
typewriters,  and  all  who  must  stoop  as  they  earn  their  daily  bread,  should 
learn  to  stop  from  time  to  time,  sit  back  in  the  chair  or  rise,  throw  back 


178  OUR   BODIES   AND    HOW  WE   LIVE 

241.  The  Natural  Heat  of  the  Body.  Everybody  knows 
that  the  surface  of  the  body  feels  warm.  Hold  the  fingers 
in  the  mouth  and  we  find  it  warm.  Put  a  thermometer, 
made  for  the  purpose,  in  the  mouth  and  under  the  tongue 
for  five  minutes,  and  it  will  register  about  98°  F.,  even  on 


B 


FIG.  113.  Photographs  of  Two  Plates  filled  with  Jelly  upon  which 
Molds  will  readily  grow ;  showing  Abundance  of  Mold  Spores 
in  the  Air. 

Plate  A  was  opened  to  the  air  for  one  minute  in  an  ordinary  room,  and  then 
closed.  The  room  was  then  swept  and  plate  B  exposed  to  the  air  for 
the  same  length  of  time.  Both  plates  were  then  set  aside  until  the 
spores  germinated,  when  the  photographs  were  made.  Plate  A  shows 
only  one  mold,  while  plate  B  contains  large  numbers.  Dusting  a  room 
produces  similar  results. 

the  coldest  day  of  midwinter.  This  is  the  natural  heat  of 
a  healthy  person,  and  it  rarely  varies  more  than  a  degree 
or  two,  except  in  disease. 

the  shoulders,  and  draw  in  ten  or  twelve  deep,  slow  inspirations,  holding  the 
breath  for  three  or  four  seconds  each  time  the  lungs  are  filled. 

These  exercises,  like  breathing  in  general,  should  always  be  done  with 
the  mouth  closed,  for  the  nose  is  the  only  proper  channel  for  the  passage 
to  and  fro  of  the  air.  A  school  teacher  who  will  interrupt  the  studies  once 
every  hour  through  the  session,  and  teach  the  class  to  do  this  breathing 
exercise,  will  be  contributing  more  than  she  can  ever  realize  to  the  future 
well-being  of  her  pupils. 


BREATHING  179 

242.  How  the  Bodily  Heat  is  produced.    The  heat  of  the 
body  is  produced  in  just  as  simple  a  manner  as  that  which 
comes  from  a  common  fire  or  a  lighted  candle.     It  is  the 
natural  result  of  the  process  of  combustion.     Our  bodies 
are  warm  because  we  are  burning  away  bit  by  bit,  just  as 
a  candle  does,  —  that  is  to  say,  by  the  union  of  carbon,  or 
charcoal,  with  oxygen.     There  is  only  this  difference :  we 
burn  wet  materials  (the  moist  tissues),  and  do  not  give  out 
flame  or  light.     In  place  of  coal  or  tallow  we  take  in  fuel 
in  the  shape  of  starch,  sugar,  and  fat  and  get  the  oxygen 
from  the  air  we  breathe. 

A  steam  engine  at  work  is  warm  because  all  the  energy 
set  free  from  the  fuel  burned  is  not  turned  into  mechanical 
work,  but  some  of  it  appears  as  heat.  So  it  is  in  our  bodies. 
Every  tiny  cell  of  every  bit  of  tissue  is  busily  at  work,  and 
its  substance  is  slowly  being  burned  at  a  low  temperature. 
Every  time  we  move,  feel,  or  think,  this  oxidation,  or  burn- 
ing, goes  on  in  all  the  tissues  of  the  body. 

Some  of  the  energy  thus  set  free  by  this  slow  combus- 
tion shows  itself  as  heat,  which  helps  to  keep  the  body 
warm  and  at  its  natural  temperature.  Thus,  animal  heat 
is  produced  and  life  maintained. 

Experiment  56.  To  show  the  natural  temperature  of  the  body. 
Borrow  a  physician's  clinical  thermometer  and  take  your  own  tem- 
perature, and  that  of  several  friends,  by  placing  the  instrument  under 
the  tongue  and  holding  it  there  for  five  minutes,  keeping  the  mouth 
closed.  Read  it  while  in  position,  or  the  instant  the  instrument  is 
removed.  The  natural  temperature  is  about  98^°  F.  The  ther- 
mometer should  be  thoroughly  cleansed  after  each  use. 

243.  How  the  Body  loses  its  Heat.     Our  bodies  are 
warmer  than  the  surrounding  air,   except  in  the  hottest 
weather  ;  hence  there  must  be  a  loss  of  heat  nearly  all 


ISO  OUR  BODIES  AND  HOW  WE   LIVE 

the  time.     Therefore  we  must  keep  making  heat  to  make 
up  for  this  continual  loss,  known  as  "radiation." 

Besides  this  loss  by  radiation  considerable  heat  is  given 
off  in  the  moisture  which  is  got  rid  of  by  the  skin  in 
forming  vapor,  or  sweat.  The  evaporation  of  this  moisture 
from  the  skin  acts  as  a  kind  of  regulator  to  keep  down  the 
excess  of  heat. 

244.  Effect  of  Alcohol  upon  the  Lungs.    We  have  learned 
in  previous  sections  that  the  most  marked  and  immediate 
effect  of  even  a  moderate  amount  of  alcohol  is  upon  the 
nerves.     This  effect  is  evident,  as  we  have  read,  in  the 
paralyzing  action  of  alcohol  upon  the  nerves  which  control 
the  muscular  walls  of  the  arteries.     These  muscles  are 
relaxed,  and  the  blood  vessels  are  dilated  and  filled  with 
an  unusual  amount  of  blood  (Sec.  215). 

This  action  of  alcohol  also  shows  itself  in  dilating  the 
minute  blood  vessels,  or  capillaries,  of  the  lungs.  This 
distension  of  the  capillaries,  if  long  continued,  tends  to 
reduce  the  size  of  the  air  sacs  and  affords  less  space  for 
the  air  which  is  needed  by  the  pulmonary  tissues.  The 
result  is  that  less  oxygen  is  supplied  to  the  blood. 

245.  Relation  of  Alcohol  to  the  Breathing  Capacity  of  the 
Lungs.    When  the  capillaries  of  the  lungs  have  been  dis- 
tended for  a  long  time  by  the  long-continued  use  of  alco- 
holic liquors,  the  walls  may  become  thickened  and  hardened. 
The  result  is  that  the  breathing  capacity  of  the  lungs  is 
diminished.     This  loss  in  breathing  space  tends  to  prevent 
the  interchange  of  gases  whereby  the  life-giving  oxygen 
is  taken  into  the  blood  and  carbon  dioxide  is  cast  out  of 
the  body. 

The  apparatus  called  the  "spirometer,"  used  by  medical 
examiners  of  life-insurance  companies  to  test  the  breathing 


BREATHING  l8l 

capacity  of  the  lungs,  often  detects  the  dram  drinker  by  his 
failure  to  reach  the  natural  breathing  capacity. 

The  repeated  dilatation  of  the  lung  capillaries  also  tends 
to  make  the  habitual  user  of  alcohol  less  able  to  resist 
attacks  of  severe  cold,  pleurisy,  and  pneumonia,  after  mak- 
ing due  allowance  for  the  exposure  to  cold  and  damp,  so 
common  with  the  intemperate.1 

246.  Alcoholics  and  Pulmonary  Consumption.    A  notion 
has  prevailed  that  the  use  of  alcoholic  liquors  may  act  as 
a  preventive  of  pulmonary  consumption.    The  records  of 
medical  science  fail  to  show  any  proof  whatever  to  support 
this  idea.     No  error  could  be  more  serious  or  more  mis- 
leading.    Alcohol,  if  it  does  not  predispose  to  pulmonary 
consumption,  as  many  believe,  certainly  furnishes  no  pro- 
tection against  it. 

247.  Alcohol  and  Bodily  Heat.    Soon  after  taking  even 
a  small  quantity  of  alcohol  there  is  a  general  feeling  of 
warmth  over  the  surface  of  the  body.     The  body  is  not 
really  warmer,  but  the  skin  feels  warmer.     On  the  con- 
trary, we  are  really  colder,  because  heat  is  more  rapidly 
lost  by  radiation  and  evaporation  from  the  surface. 

1  Most  familiar  and  most  dangerous  is  the  drinking  man's  inability  to 
resist  lung  diseases.  —  ADOLPH  FRICK,  M.D. 

There  is  good  reason  to  believe  that  the  use  of  spirituous  liquors  among 
the  working  classes  of  the  country  is  productive  of  consumption  and  tuber- 
culous diseases  to  an  extent  far  beyond  what  is  usually  imagined.  The 
blanched,  cadaverous  aspect  of  the  spirit  drinker  bespeaks  the  condition 
of  his  internal  organs.  The  tale  of  his  moral  and  physical  degradation  is 
indelibly  written  on  his  countenance.  The  evil,  however,  does  not  rest  here  ; 
for  by  destroying  his  own  health  he  entails  on  his  unhappy  offspring  the 
predisposition  to  tuberculous  diseases.  —  SIR  JAMES  CLARK,  M.D. 

Alcohol  is  a  frequent  cause  of  consumption  by  its  power  of  weaken- 
ing the  lunfts.  Every  year  we  see  patients  who  attend  the  hospital  for 
alcoholism  come  back  after  a  period  to  be  treated  for  consumption.  — 
DR.  LEGENDRE,  a  famous  Paris  physician, 


182  OUR   BODIES   AND   HOW  WE   LIVE 

The  skin  is  warmer  after  taking  alcoholic  liquor,  because 
the  nerves  that  regulate  the  threadlike  blood  vessels  on 
the  surface,  being  partly  paralyzed  or  deadened,  dilate  and 
allow  more  blood  to  flow  through  them.  Hence  more  blood 
is  sent  from  the  central  parts  of  the  body  to  the  surface. 
There  is  no  real  increase  of  heat :  the  surface  is  warmed 
for  the  time  at  the  expense  of  the  inner  and  deeper  por- 
tions of  the  body. 

This  surface  warmth  is  rapidly  lost  by  radiation,  and  the 
general  heat  of  the  body  is  lowered  below  its  natural  tem- 
perature. The  bodily  temperature  is  partly  regulated  by 
-the  surface  circulation ;  and  when  this  control  is  lost,  as  it 
is  by  alcohol,  the  body  is  cooled  by  the  undue  amount  of 
blood  carried  to  the  surface. 

The  notion  that  a  dose  of  some  alcoholic  liquor  taken 
after  exposure  or  bathing  will  prevent  one  from  taking 
cold  is  erroneous.  The  alcohol,  by  irritating  the  delicate 
lung  tissues  and  lining  of  the  air  passages,  and  reducing 
the  temperature  of  the  body,  makes  one  more  liable  to 
colds,  coughs,  pneumonia,  etc.  When  we  feel  chilly,  the 
best  thing  to  do  is  to  get  thoroughly  warmed  as  quickly 
as  possible,  either  by  active  exercise  or  by  artificial  heat. 

248.  Alcohol  and  the  Endurance  of  Extremes  of  Heat  or 
Cold.  Experience  has  proved,  time  and  time  again,  that 
alcohol  lessens  the  power  to  endure  the  extremes  of  heat 
or  cold  for  any  length  of  time.  Arctic  explorers  strictly 
forbid  the  use  of  alcoholic  liquor  among  their  men  because 
they  know  that  exposure  to  severe  cold  can  be  endured 
far  better  without  it.  So  well  is  this  effect  of  alcohol 
known  by  the  people  of  the  coldest  regions  of  Canada,  that 
they  will  seldom  take  even  a  single  glass  of  spirits  when 
exposed  to  severe  cold. 


BREATHING  183 

Army  life  is  perhaps  the  best  possible  test.  It  is  the 
almost  universal  experience  of  British  army  officers  who 
have  led  their  men  through  arduous  campaigns  in  the 
hottest  parts  of  Africa,  and  who  have  given  much  study 
to  the  question,  that  alcohol,  so  far  from  being  an  aid  to 
endure  severe  exertion  and  to  resist  great  extremes  of  heat, 
acts  as  a  positive  injury.1 

General  Kitchener  prohibited  all  drinks  containing  alco- 
hol in  the  Sudan  campaign.  Respecting  the  result,  a  war 
correspondent  said  :  "  Of  one  thing  I  am  sure,  —  that  the 
mortality  from  fever  and  other  diseases  during  the  Atbara 
campaign  and  the  final  Omdurman  campaign  would  have 
been  infinitely  greater  than  it  was  if  alcoholic  liquors  had 
been  allowed  as  a  beverage,  or  even  as  an  occasional 
ration." 

Lord  Roberts,  the  British  commander  in  the  Boer  war, 
claims  that  the  effective  power  of  an  army  to  endure  extreme 
heat  and  cold  is  always  in  proportion  to  the  number  of 
total  abstainers  in  the  ranks. 

1  A  party  of  engineers  were  surveying  in  the  Sierra  Nevadas.  They 
camped  at  a  great  height  above  the  sea  level,  where  the  air  was  very  cold, 
and  they  were  chilled  and  uncomfortable.  Some  of  them  drank  a  little 
whisky  and  felt  less  uncomfortable;  some  of  them  drank  a  lot  of  whisky 
and  went  to  bed  feeling  very  jolly  and  comfortable  indeed.  But  in  the 
morning  the  men  who  had  not  taken  any  whisky  got  up  in  good  condition ; 
those  who  had  taken  a  little  whisky  got  up  feeling  very  miserable;  the 
men  who  had  taken  a  lot  of  whisky  did  not  get  up  at  all :  they  were  simply 
frozen  to  death.  They  had  warmed  the  surface  of  their  bodies  at  the 
expense  of  their  internal  organs. — T.  LEANDER  BRUNTON,  M.D.  (St.  Bar- 
tholomew Hospital,  London),  in  Lectures  on  the  Action  of  Medicine. 


184  OUR  BODIES   AND   HOW  WE   LIVE 


QUESTIONS  ON  THE  TEXT 

I.  What  may  be  said  in  a  general  way  of  the  act  of  breathing? 
2.  What  have  we  learned  in  previous  chapters  about  food  and  the 
blood?     3.  What  have  we  learned  previously  about  the  circulation 
of  blood  in  the  lungs  ?     4.  State  in  a  general  way  the  twofold  object 
of  breathing.     5.  Through  what  passages  is  air  drawn  into  the  lungs  ? 
6.  What  are  the  nostrils?     7.  Describe  the  windpipe.     8.  What  is 
the  epiglottis  ?     9.  Describe  the  larynx.     10.  Into  what  two  branches 
is  the  windpipe  divided  after  entering  the  chest  cavity? 

II.  Describe    the    bronchial    tubes.     12.  What    are    the    lungs? 

13.  What   is   meant  by  the   lobes   and   the   lobules  of  the  lungs? 

14.  What  is  the  pleura?     15.  How  may  the  respiratory  sounds  be 
plainly  heard  ?     16.  What  useful  purpose  do  the  cilia  serve  ? 

17.  How  may  we  note  the  general  movements  of  breathing  in  our 
own  persons?  18.  Give  brief  definitions  of  inspiration,  expiration, 
and  respiration.  19.  Explain  in  some  detail  the  mechanical  move- 
ments in  the  act  of  breathing.  20.  What  part  do  the  intercostal 
muscles  play  in  the  process  of  breathing? 

21.  Of  what  is  the  air  we  breathe  composed?  22.  How  is  the  air 
changed  in  breathing?  23.  Mention  some  other  changes  in  the  air 
that  take  place  during  breathing.  24.  What  is  meant  by  the  dif- 
fusion of  gases  ?  25.  What  exchange  of  gases  takes  place  between 
the  blood  and  the  air  in  breathing  ?  26.  What  does  the  blood  gain 
and  lose  in  the  process  of  breathing?  27.  What  do  the  air  sacs  gain 
and  lose  in  breathing?  28.  Describe  the  process  of  respiration  in 
all  of  the  tissues.  29.  Mention  some  things  that  may  make  the  air 
impure.  30.  How  may  the  germs  of  disease  be  carried  in  the  air  ? 

31.  Explain  how  the  sputa  of  persons  suffering  from  pulmonary  con- 
sumption may  become  a  source  of  contagion.  32.  Give  some  practical 
hints  about  ventilation.  33.  Why  and  how  should  schoolrooms  be 
ventilated  ?  34.  How  can  we  ascertain  the  temperature  of  the  body  ? 

35.  Explain   in    a  general  way  how  the  bodily  heat  is  produced. 

36.  How  does  the  body  lose  its  heat?     37.  What  is  the  general  effect 
of  alcohol  upon  the  lungs  ?     38.  What  effect  does  alcohol  have  upon 
the  breathing  capacity  of  the  lungs  ?     39.  How  does  alcohol  modify 
the  bodily  heat?     40.  Explain  how  alcohol   lessens   the   power  to 
endure  the  extremes  of  heat  and  cold. 


CHAPTER    IX 
THE  SKIN  AND  THE  KIDNEYS 

249.  How  our  Bodies  are  covered.    The  skin  is  the  out- 
side covering  of  the  body.     We  all  know  how  painful  and 
tender  any  part  of  the  body  is  when  this  covering  has  been 
torn,  cut,  blistered,  burned,  or  otherwise  hurt. 

Kind  nature  has  given  us  a  firm,  elastic,  and  tight-fitting 
outside  garment.  It  is  easily  kept  clean,  and  never  wears 
out.  It  is  soft  and  thin  enough  to  enable  us  to  feel  objects 
easily,  yet  thick  and  strong  enough  to  allow  us  to  do  this 
without  pain. 

250.  The  Skin  and  its  Two  Layers.    The  skin  consists  of 
two  layers.     The  outer  one  has  neither  blood  vessels  nor 
nerves,  and  is  called  the  cuticle,  scarfskin,  or  epidermis. 

The  deeper  layer,  called  the  true  skin,  or  dermis,  is  so 
highly  sensitive  that,  were  it  not  for  the  outer  layer,  we 
could  not  endure  life.  Most  of  us  are  familiar  with  the 
delicate  pink  skin  which  is  exposed  when  the  outer  skin 
is  removed  by  a  blister,  or  rubbed  off  by  some  slight 
accident.  The  surface  feels  raw,  and  from  it  oozes  a  little 
clear  fluid  called  "  lymph,"  or  perhaps  a  little  blood.  Beneath 
the  true  skin  there  is  a  layer  of  fat  which  gives  roundness 
and  softness  to  the  figure. 

251.  The   Scarfskin.     The  deeper  portion  of  the  scarf- 
skin  is  constantly  producing  millions  of  little  cells  to  take 
the  place  of  the  flat,  horny,  and  lifeless  scales  of  the  outer 

185 


186  OUR   BODIES   AND   HOW   WE   LIVE 

portion,    which    are    continually   dropping    off    or    being 
removed  by  friction. 

When  these  flattened  scales  are  pressed  together,  they 
become  flatter  and  flatter  ;  and  thus  the  hard,  horny  skin 
is  made,  which  is  seen  in  places  where  the  wear  and  tear  is 
considerable,  as  in  the  palms  of  the  hands  and  the  soles 
of  the  feet.  The  callous  places  on  the  hands  of  the  black- 
smith, the  carpenter,  or  the  washerwoman  are  familiar. 

252.  What  gives  the  Skin  its  Color.  In  the  deeper  parts 
of  the  scarfskin  are  tiny  specks  of  coloring  matter,  hid  in 
little  cells.  These  give  the  skin  its  color.  In  the  fairer 

races,  these  specks  are  of 
a  pinkish  color  ;  in  the  dark 
races,  the.  pigment  cells 
are  brown  or  nearly  black, 
and  more  closely  crowded 
together. 

FIG.  114.     A  Layer  of  the  Outer  Skin         The   rays    of    the    SUn 
from  the  Palm  of  the  Hand.  serve  tQ  darken  thege 


specks,  as  is   seen  in  the 

parts  of  the  body  exposed  to  direct  sunlight.  We  often 
see  on  the  persons  of  laboring  and  athletic  people  a  sharp 
line  drawn  between  parts  of  the  arm  or  neck  exposed  to 
the  sun's  rays,  and  other  parts  generally  covered  with 
clothing.  Some  persons,  however,  tan  much  more  readily 
than  others.  When  the  pigment  changes  in  spots,  we 
call  them  freckles. 

Experiment  57.  Take  a  very  fine  and  perfectly  clean  needle 
and  run  the  point  carefully  beneath  the  thin  outer  layer  of  the  skin 
at  the  junction  of  the  ringers  with  the  palm  of  the  hand.  Note 
that  the  point  of  the  needle  is  not  felt  and  that  there  is  no  flow 
of  blood. 


THE    SKIN   AND   THE    KIDNEYS  187 

253.  The  True  Skin.     The  true  skin,  or  dermis,  is  a  firm, 
elastic  structure  resting  on  meshes  of  a  tissue  something 
like  damp,  raw  cotton,  which  loosely  fasten  the  skin  to  the 
parts  beneath.     It  is  the  true  skin  which,  in  the  lower  ani- 
mals, is  made  into  leather  by  the  process  of 

tanning.     In  this  layer  also  are  the  nerves, 
blood  vessels,  and  absorbents  of  the  skin. 

When  the  true  skin  is  destroyed,  a  scar 
results.  White  scars,  especially  on  the 
hands,  due  to  deep  cuts,  and  scars  from 
smallpox,  deep  burns,  and  other  injuries 
to  this  layer  of  the  skin,  are  often  seen. 

The  true  skin  is  richly  supplied  with 
nerves  and  blood  vessels  so  closely  netted  FIG.  115.    Epidermis 
together  that  it  is  next  to  impossible  to     from  the  Bottom  of 
prick  the  skin  anywhere  with  the  point 
of  a  needle  without  drawing  blood  and  feeling  pain. 

Experiment  58.  Stretch  the  thumb  and  forefinger  of  the  left  hand 
wide  apart.  Gently  prick  the  skin  with  the  point  of  a  fine,  clean 
needle.  Note  how  sensitive  the  true  skin  is,  and  how  readily  a  drop 
of  blood  may  flow. 

Experiment  59.  Press  the  thumb  of  the  right  hand  tightly  into 
the  left  palm.  Remove  the  thumb  quickly.  Note  the  difference  in 
color  of  the  spot  pressed  and  that  of  the  skin  near  by. 

254.  The  Skin  and  the  Sense  of  Touch.     The  outer  sur- 
face of  the  true  skin  rises  up  into  the  epidermis  so  as  to 
form  little  hillocks,  or  papillae,  into  which  run  the  capillaries 
and  the  nerves. 

In  the  papillae  are  little  round  or  oval  bodies,  called 
touch  corpuscles  (Sec.  340). 

These  papillae  are  very  numerous  everywhere,  but  are 
thickest  where  the  sense  of  touch  is  most  acute,  as  on 


i88 


OUR   BODIES  AND   HOW  WE   LIVE 


the  tips  of  the  fingers.  They  are  arranged  in  rows,  like 
hills  of  corn,  and  sometimes  in  whorl-like  patterns,  which 
are  plainly  seen  with  a  magnifying  glass  on  the  palms  of 
the  hands  or  the  balls  of  the  fingers. 

Experiment  60.  Dip  the  end  of  a  wooden  toothpick  into  some 
thick  ink  and  spread  it  very  thin  over  the  end  of  the  forefinger,  or 
press  the  end  of  the  finger  on  a  color  pad.  Now  press  the  finger  tip  on 

a  piece  of  heavy,  uncoated  paper. 
Study  the  impression  made  by 
the  ridges  on  the  finger. 


Experiment  61.  The  living  skin 
can  be  examined  only  in  a  gen- 
eral way.  Stretch  and  pull  it,  and 
notice  that  it  is  elastic.  Examine 
the  outer  skin  carefully  with  a 
strong  magnifying  glass.  Study 
the  papillae  on  the  palms.  Scrape 
off  with  a  blunt  knife  a  few  bits  of 
the  scarfskin,  and  examine  them 
with  a  magnifying  glass. 


FIG.  116.     Papillae  of  the  Skin  in 
the  Palm  of  the  Hand. 

In  each  papilla  are  seen  vascular  loops 
(dark  lines)  running  up  from  the  vas- 
cular network  below;  the  tactile  cor- 
puscles (white  lines)  which  supply  the 
papillae  are  also  shown. 


255.  How  the  Skin  may 
absorb  Poison.  The  outer 
skin  helps  to  protect  the  true 
skin  from  poisons.  Lead,  mercury,  and  other  injurious 
substances  will  not  enter  the  blood  and  affect  the  health, 
unless  they  are  actually  rubbed  through  the  dermis ;  but  if 
there  is  a  scratch  or  sore,  so  that  the  true  skin  is  exposed, 
the  poisons  may  be  absorbed  into  the  blood  with  great 
rapidity. 

Workers  in  lead,  looking-glass  silverers,  and  phosphorus 
match  makers  ought,  therefore,  to  take  great  care  to  cover 
the  smallest  scratches  on  their  hands.  "  Lead  colic  "  and 
"wrist  drop"  are  familiar  instances  of  lead  poisoning. 


THE  SKIN   AND   THE   KIDNEYS 


189 


FIG.  117.     The  First  Vaccination. 

This  picture  is  based  upon  a  photograph  of  a  painting  exhibited  many 
years  ago  in  the  Paris  Salon.  It  represents  the  crowning  experiment  of 
Dr.  Edward  Jenner,  a  famous  English  physician  and  the  discoverer  of  vac- 
cination. The  experiment  was  performed  on  a  boy  whom  Jenner  inocu- 
lated with  matter  taken  from  the  hand  of  a  milkmaid  who  had  been  directly 
infected  by  the  cow.  This  was  on  the  I4th  of  May,  1796,  —  more  than  a 
century  ago. 

The  picture  is  used  by  the  kind  permission  of  William  Wood  &  Co.,  publishers. 


OUR   BODIES   AND   HOW   WE   LIVE 


Cheap  underclothes,  as  colored  stockings,  are  often  dyed 
with  preparations  of  lead.  Such  articles  should  be  thor- 
oughly washed  before  they  are  worn.  Many  hair  dyes 
contain  lead,  and  may  cause  lead  poisoning. 

256.  Absorption  of  Infectious  Matter  by  the  Skin.     The  fact 
that  certain  infectious  matters  are  -easily  and  rapidly  absorbed 
by  the  skin  has  long  been  utilized  by  people  who  have  learned 
to  safeguard  themselves  against  the  ravages  of  smallpox.     A 
bit  of  the  outer  skin  is  scraped  away  with   a  pocketknife  or 
some  other  convenient  instrument.     On    the   moist,  denuded 
skin  is  placed  the  vaccine  matter  from  a  quill,  or  even  matter 
obtained  from  a  smallpox  pustule. 

Many  years  ago,  when  smallpox  was  very  common  and 
fatal  in  England,  the  attention  of  a  young  medical  student, 
named  Jenner,  was  forcibly  attracted  to  the  nature  of  the  dread 
disease  in  the  following  manner.  One  day  a  young  milkmaid 
came  to  seek  his  advice.  Speaking  of  smallpox,  the  girl  said, 
"I  cannot  take  that  disease,  .for  I  have  had  cowpox."  Jenner 
began  a  long  series  of  experiments  and  observations  to  explain 
this  remarkable  fact.  The  actual  discovery  of  vaccination  was 
delayed  for  many  years  (Fig.  117  and  Sec.  427). 

257.  Structure  of  the  Hair.     A  hair  is  made  up  of  horny 
cells  of  the  outer  layer  of  the  skin  altered  in  shape  and 
structure.     It  grows  from  little  sacs  in  the  true  skin  called 
hair  follicles. 

Every  hair  has  two  parts,  —  the  root  and  the  free  end. 
The  root  is  somewhat  pear-shaped  and  is  sunk  in  its  sac, 
or  follicle,  like  a  post  into  the  ground.  In  the  bottom  of 
this  sac  is  a  little  hair  papilla,  quite  different  from  the  papillae 
of  the  skin.  From  this  comes  material  for  the  growth  of 
the  hair.  As  long  as  this  papilla  is  not  destroyed,  the  hair 
will  grow.  If  we  pull  out  the  hair  from  the  roots,  it  will 


THE    SKIN   AND   THE    KIDNEYS 


grow  again.     If  we  destroy  this   papilla,  the  hair  never 
grows  again.1 

The  hair  follicles  are  well  supplied  with  nerves,  hence  it 
hurts  to  have  the  hair  pulled. 

258.  How  the  Hairs    grow.     Hairs    grow   from    cells 
pressed  together  lengthwise,  so  that  they  are  drawn  out 
into  fibers  instead  of  being  flattened  into  scales.     Hence 
they  grow  only  in  length.     On  the  outer  surface  the  cells 
form  a  sort  of  bark, 

overlapping  each  ^^^ 
other  something  like 
the  shingles  on  a  roof. 
The  coloring  mat- 
ter is  contained  in 
the  cells.  It  is  this 
pigment  which  gives 
the  great  variety  in 
color.  The  hair  usu- 
ally becomes  gray  or 
white  as  old  age 
comes  on.  The  pigment  is  absent  and  the  cells  are  filled 
with  air  bubbles. 

259.  Muscles  that  control  the  Hairs.     The    hairs,    or 
rather  the  parts  of  the  skin  close  to  them,  are  provided 
with  tiny  muscles.     They  run  from  the  bottom  of  each 
hair  follicle  in  a  slanting  direction,  and  end  in  the  outer 
part  of  the  true  skin.     When  they  contract  they  cause  the 

1  It  is  useless,  or  worse  than  useless,  to  try  to  rid  one's  self  of  unsightly 
hairs  or  hair  moles  on  the  face.  If  we  pull  them  out  with  tweezers,  or  cut 
or  shave  them  off,  they  are  sure  to  grow  again,  coarser  and  more  unsightly 
than  before.  Remedies  advertised  to  remove  superfluous  hairs  are  usually 
worthless  or  dangerous.  The  hair  papillae  must  be  destroyed  to  stop  the 
growth  of  hair,  and  this  is  no  simple  matter. 


FIG.  118.     BLACKBOARD  SKETCH. 

Surface  of  Palm  of  the  Hand,  showing  Open- 
ings of  Sweat  Glands  and  Grooves  between 
Papillae  of  the  Skin. 

Magnified  4  diameters. 

In  the  smaller  figure  the  same  epidermal  surface  is 
shown  as  seen  with  the  naked  eye. 


192 


OUR  BODIES  AND    HOW  WE   LIVE 


hair  to  stand  more 
up  a  little.     Thus, 

A 


FIG.  119. 

BLACKBOARD  SKETCH. 
Cross-Section  of  Skin. 
Magnified  30  diameters. 
A,  outer  layer  of  cuticle; 
£,  deeper  layer  of  cuticle ; 
C,  duct  of  sweat  gland; 
Z>,  true  skin ;  E,  sublayer 
of  true  skin,  with  colum- 
nar cells.  The  blood  ves- 
sels are  injected  to  show 
black. 


or  less  erect,  and  the  skin  to  bunch 

at  the  sight  of  a  dog,  the  hairs  on  a 

cat's  back  become  erect  and  bristling. 

Any  one  who  has  been  frightened 
suddenly,  or  has  taken  a  chilly  bath, 
knows  what  it  is  to  have  "goose  flesh." 
These  muscles  also  act  to  force  oil 
out  of  the  oil  glands  (Fig.  125). 

The  hair  serves  to  protect  the  parts 
it  covers  from  heat  and  cold.  On  the 
head,  the  hair  helps  to  protect  the 
skull  from  injuries  and  the  brain  from 
extremes  of  heat  and  cold. 

260.  The  Nails.  The  nails  are 
horny  cells^of  the  epidermis  in  a  hard- 
ened and  thickened  form.  They  grow 
from  roots  which  are  lodged  in  a 
groove  of  the  skin,  somewhat  as  a 
watch  crystal  is  fitted  into  its  case. 
The  part  which  is  beneath  the  skin 
is  called  the  root,  and  the  remaining 
part  the  body.  (Figs.  122-124). 

The  nail  rests  upon  a  bed,  called 
the  nail  bed  or  matrix,  to  which  it  is 
firmly  fastened.  Nails  grow  from  the 
root,  and  as  long  as  this  is  not  injured 
they  are  not  lost  or  disfigured  by 
splinters,  blows,  and  bruises. 

Disease  or  injury  of  the  root  gen- 
erally results  in  a  badly  shaped  nail. 
The  nails  serve  by  their  horny  tex- 
ture to  protect  the  outer  portions  of 


THE    SKIN   AND   THE    KIDNEYS 


193 


the  ends  of  the  fingers  and  toes  from  injury,  and  to  give 
a  support  for  the  fleshy  ends. 

261.  The  Care  of  the  Finger  Nails.  The  finger  nails  grow 
out  about  three  times  a  year.  They  should  be  trimmed 
once  a  week,  leaving  them  long  enough  to  protect  the 
ends  of  the  fingers.  Nails  should 
never  be  trimmed  to  the  quick. 
They  should  not  be  cleaned  with 
anything  harder  than  a  brush  or 
a  bit  of  soft  wood.  They  should 
not  be  scraped  with  a  penknife  or 
anything  metallic,  as  it  destroys 
the  delicacy  of  their  structure, 
and  gives  them  an  unnatural 
thickness. 

"  Hangnails  "  are  caused  by  the 
skin  fastening  itself  to  the  nail, 
which,  growing  outward,  drags  the 
skin  along  with  it,  stretching  it 
until  one  end  gives  way.  To  pre- 
vent this,  the  skin  should  be  loos- 
ened from  the  nail  once  a  week, 

not  with  a  knife  or  scissors,  but   FIG.  120.  Cross-Section  of  One 
with  something  blunt,  such  as  an 
"  orange  stick,"  made  for  this  pur- 
pose, the  small  end  of  a  nailbrush,  or  an  ivory  paper  cutter.1 


Half  of  a  Human  Hair. 
Magnified  about  300  diameters. 


1  An  ingrowing  toe  nail  often  causes  much  pain  and  inconvenience.  It  is 
found  most  commonly  on  the  side  of  the  great  toe,  although  it  may  occur 
on  any  one  of  the  smaller  toes.  Ill-fitting  boots  and  shoes  in  which  the 
toes  are  cramped  together  usually  cause  the  trouble. 

The  toe  nails  should  always  be  cut  off  square,  at  a  right  angle  to  the 
axis  of  the  toe,  and  should  never  be  pared  close  and  rounded  off  at  the 
sides  parallel  with  the  extremity  of  the  toe.  If  they  are  rounded  there  is 


194 


OUR  BODIES  AND   HOW  WE   LIVE 


262.  The  Oil  Glands. 

clustered   together   like 


FIG.  121.  Section  of  Lower 
Portion  of  a  Hair  and  Hair 
Follicle. 

Highly  magnified. 

A,  membrane  of  hair  follicle, 
showing  cells  with  nuclei  and 
pigmentary  granules ;  B,  exter- 
nal lining  of  root  sheath ;  C, 
internal  lining  of  root  sheath ; 
D,  cortical  or  fibrous  portion 
of  hair  shaft ;  E,  medullary  por- 
tion (pith)  of  shaft;  F,  hair 
bulb,  showing  its  development 
from  cells. 


The  oil  glands  are  little  round  sacs 

a  bunch  of  grapes,   with  a  tube 

which  opens  into  the  hair  follicles. 

Generally  there  are  two  to  each 
hair,  but  in  some  places  there  are 
from  four  to  eight  araund  a  hair, 
making  a  kind  of  collar  about  it. 
These  glands  furnish  a  natural 
dressing  for  the  hair  and  keep  it 
moist  and  glossy.  They  also  keep 
the  surface  of  the  skin  soft  and 
flexible. 

In  some  places  the  oil  glands, 
as  upon  the  nose,  chin,  and  fore- 
head, are  large,  and  the  hairs  very 
small ;  hence  it  often  occurs  that 
they  open  directly  upon  the  skin. 
In  these  openings  the  oil  is  likely 
to  collect  and  become  hard. 

Bits  of  dust  get  into  these 
glands,  acting  like  plugs,  and 
show  themselves  as  small  black 
specks,  incorrectly  called  "flesh 
worms,"  because  of  the  resem- 
blance which  these  little  masses 


nothing  left  to  support  the  side  of  the  toe,  and  the  pressure  of  the  shoe 
then  causes  the  fleshy  parts  to  ride  up  over  the  side  of  the  nail,  and  as  the 
latter  grows  it  has  to  cut  its  wray  into  soft  parts,  for  it  has  nowhere  else  to  go. 
The  wound  so  caused  cannot  heal,  for  the  sharp  side  of  the  nail  is  always 
cutting  farther  into  it  and  producing  irritation.  Soon  it  becomes  inflamed ; 
then  matter  forms,  "  proud  flesh  "  grows  up  over  the  side,  and  a  most  pain- 
ful and  crippling  condition  may  result.  Home  treatment  often  makes  bad 
matters  worse.  A  chiropodist's  services  are  often  needed. 


THE    SKIN   AND    THE    KIDNEYS 


195 


have  to  a  worm.  This  oily  secretion,  which  might  well  be 
called  nature's  hair  oil,  is  perfectly  fluid  in  a  healthy  skin, 
and  at  the  temperature  of  the  body, 

263.  The  Sweat  Glands.  The  sweat 
glands  consist  of  very  fine  tubes,  about 
one  quarter  of  an  inch  long,  coiled  into 

knots.      From 
|  each    knot    a 

canal,  called  a 

sweat  duct,   rises 

up  through  the 

dermis    and, 

piercing  the  epi- 

dermis  in  cork- 

screw fashion, 

opens  on  the  surface  of  the  skin. 
The  openings,  or  small  pits,  of  these 

*  f 


FIG.  122.  Concave  or 
Adherent  Surface  of 
Nail. 

A,  border  of  the  root ;  B, 
whitish  portion  of  semi- 
lunar  shape ;  C,  body  of 
nail.  The  continuous 
line  around  border  rep- 
resents the  free  edge. 


FIG.  1 23.     Nail  in 
Position. 


A,  section  of  cutaneous  fold 

turned   back  to   show    sweat  glands  are  set  in  rows,  as  may 

root  of  nail;  B  cutane-      be     seen     by     a     common     magnifying 

J  J      & 

glass, 


ous    fold   covering   root 

of    nail;     C,    semilunar 

whitish  portion;  D,  body      cially    on 

of  nail.  J 

the  palms 

of  the  hands  between  the  ridges 
of  the  skin.     On  the  sole  of  the 

foot   and   the   palm   of   the  hand    FIG.  124.    Longitudinal  Section 

they  are  very  numerous,   there  of  a  Finger  Nail 

,  ,  ,  ,        f    A,  last  bone  of  finger  :  B,  true  skin 

being  some  three    thousand  of      on  the  dorsal  surface  of  finger. 


them  to  the  square  inch ;  while 

on    the    cheeks   there  are  only 

about  five  hundred  and  fifty  in 

the  same  space,  and  about  twelve  hundred  to  the  square 

inch  on  the  forehead.    At  a  rough  estimate,  there  are  more 


C,  outer  skin;  D,  true  skin;  E, 
bed  of  nail;  F,  superficial  layer 
of  nail ;  //,  true  skin  of  pulp  of 
finger. 


196  OUR  BODIES   AND   HOW  WE   LIVE 

than  two  million  sweat  glands  in  the  whole  body.  If  they 
were  laid  end  to  end,  they  would  stretch  to  a  distance  of 
nearly  ten  miles. 

Experiment  62.  Study  the  openings  of 
the  sweat  glands  with  the  aid  of  a  strong 
magnifying  glass.  They  are  conveniently 
examined  on  the  palms. 

264.  The  Sweat,  or  Perspiration. 
The  sweat,  or  perspiration,  is  a  colorless, 
salty  fluid,  with  a  peculiar  odor.  It 
is  a  part  of  the  waste  matter  of  the 
tissues  which  has  been  filtered  from 
the  blood  and  is  got  rid  of  through 
these  busy  little  glands  in  the  skin. 

These  glands  are  always  at  work 
pouring  out  sweat.  This  may  not  be 
evident  to  the  eye  or  to  the  touch, 

because  it  evaporates  into  the  air  as 
FIG.  125.     BLACKBOARD 

SKETCH.  fast  as  it  is  formed.      In  hot  weather, 

Hair  and  Hair  Follicle,    or  during  exercise,  the  sweat  is  poured 
A,  root  of  hair;  B,  bulb    out  faster  than  it  can  evaporate.     It 

of  hair;  C,  internal  root        ft         coHects  m  drops  and  runs  down 

shield;   D,  external  root 

shield ;  £,  external  mem-     Our  f  aCCS. 

cl7  °fi^"a«kctdmUt:  The  average  daily  quantity  of  per- 
follicle;  H,  compound  oil  spiration  is  not  far  from  two  pints, 
tlptVuS  £|  but  this,  of  course,  is  much  increased 
opening  of  hair  follicle,  in  hot  weather.  It  varies  greatly, 
according  to  what  we  are  doing,  the 

condition  of  health,  how  we  are  clothed,  and  the  tempera- 
ture of  the  surrounding  atmosphere.1 

1  Horses  sweat  all  over  the  body,  and  so  do  human  beings,  but  monkeys, 
it  is  said,  sweat  only  on  the  hands,  feet,  and  face.     In  animals  that  perspire 


THE   SKIN   AND   THE   KIDNEYS 


197 


Experiment  63.  Press  the  palm  of  the  hand  gently  on  a  hand  glass 
or  mirror.  If  convenient,  have  the  surface  of  the  glass  cold.  Repeat 
the  process  with  the  back  of  the  hand.  Note  any  difference  in  the 
relative  amounts  of  perspiration.  Try 
these  experiments  on  a  very  hot  and  a 
very  cold  day,  and  note  the  difference 
in  the  activity  of  the  skin. 

265.  Why  we  sweat.  The  most 
important  function  of  the  sweat 
is  to  regulate  the  temperature  of 
the  body  by  evaporation  from  its 
surface.  We  fan  ourselves  on  a 
hot  day  to  hasten  this  evaporation 
of  the  moisture  on  the  skin.  In 
hot  weather,  and  after  taking  a  hot 
drink  or  a  hot-air  bath,  the  skin 
does  its  best  to  reduce  the  tem- 
perature, and  thus  works  all  the 
harder  in  pouring  out  the  sweat 
more  profusely.  When  one  is  per- 
spiring freely,  it  is  highly  impru- 
dent to  sit  in  a  cool  draught ;  for 
this  evaporation  may  be  suddenly 
checked,  and  we  are  then  apt  to 
take  cold.1 

but  little,  the  cooling  of  the  body  is  effected 
chiefly  by  evaporation  from  the  tongue,  as 
we  see  in  the  case  of  a  panting  dog. 

Profuse  sweating  is  very  common  in 
cases  of  debility  and  in  excessively  stout 
persons.  It  occurs  also  in  connection  with 
various  diseases.  Sudden  emotion  may 
cause  increased  perspiration. 

1  Some  people  are  afflicted  with  a  natu- 
rally strong  and  disagreeable  odor  of  the 


FIG.  126.    BLACKBOARD 
SKETCH. 

Vertical  Section  of  the  Human 
Skin. 

Magnified  30  diameters. 

Showing  three  outer  layers  of  the 
cuticle,  —  two  in  black  and  a 
middle  light  layer.  Below  the 
inner  dark  layer,  the  active 
layer  (rete  mucosuni)  is  well 
shown.  All  below  is  the  true 
skin.  The  tortuous  course  of 
a  sweat  gland  is  well  marked. 
The  two  round  black  spots  are 
fat  cells. 


198 


OUR  BODIES   AND    HOW   WE    LIVE 


266.  Why  we  should  take  care  of  the  Skin.  Many 
thousands  of  sweat  glands  in  the  skin,  acting  like  drainage 
tubes,  together  with  the  countless  oil  glands,  pour  out  daily 
about  two  pounds  of  sweat,  oil,  and 
other  used-up  matters  through  the 
hard-worked  skin. 

The  perspiration  evaporates  and 
leaves  the  solid  and  oily  matters 
to  plug  the  mouths  of  these  tiny 
sewer  pipes. 

The  dead  scales  of  the  scarfskin 
are  continually  dropping  off.  They 
become  sticky  with  the  oil,  and, 
getting  entangled  in  the  meshes 
of  the  clothing,  become  glued  in  a 
kind  of  thin  crust  to  the  surface 
of  the  body.  This,  if  not  regularly 
washed  off,  attracts  dirt  and  dust. 

The  glands  of  the  skin  thus  get 
choked  up  and  are  not  able  to  do 
their  work  properly.  Other  organs, 

Vertical  Section  of  Skin    Such  aS  the  lunSS  and  the  kldneyS> 

showing  Sweat  Gland  with  now  have  to  do  their  own  work  and 
its  Duct  help  do  that  of  the  skin  besides. 

The   convoluted   gland  is  seen    The  balance  Qf   health  is  disturbed 
surrounded  with  fat  cells  and 

may  be   traced   through  the  ,,.     .  j 

true  skin  to  its  outlet  in  the   perspiration.     In  some  cases  this  is  caused 

horny  layers  of  the  outer  skin,    by  ill  health,  but  in   many,  perhaps  most, 

cases,  it  is  natural  to  the  sufferer,  and  can 

only  be  overcome  in  a  measure  by  extreme  care  of  the  person  and  attention 

to  the  bath.     Sponging  the  body  with  water  containing  a  few  drops  of 

ammonia  may  afford  some  relief. 

Frequent  change  of  clothing  will  be  necessary,  and  dress  shields  should 

be  worn  by  all  who  have  this  unpleasant  infirmity,  and  the  same  suit  or 

dress  should  never  be  worn  on  two  consecutive  days. 


FIG.  127. 
BLACKBOARD  SKETCH. 


THE   SKIN    AND    THE    KIDNEYS  199 

because  the  blood  is  not  properly  purified,  and  disorders 
of  various  kinds  are  almost  sure  to  result. 

267.  Baths  and  how  to  take  them.     The  first  object  in 
using  soap  and  water  on  the  skin  is  to  keep  it  clean ;  the 
second,  to  give  vigor  and  strength  to  the  whole  body. 

It  takes  very  little  time,  expense,  or  trouble  to  take  a 
daily  bath  of  some  sort.  A  hand  basin,  a  sponge,  a  strip 
of  cotton  flannel,  a  piece  of  Castile  soap,  a  gallon  of  water, 
and  a  towel  are  all  that  are  required.  Even  rubbing  the 
body  every  day,  first  with  a  damp  towel  and  afterwards 
very  briskly  with  a  dry  one,  will,  in  most  cases,  keep  the 
skin  clean  enough  during  the  week,  provided  a  bath  with 
warm  water  and  soap  is  taken  at  the  end  of  the  week. 

Coarse  and  rough  towels  should  always  be  used  if  the 
skin  will  bear  it.  Some  skins  are  very  active  and  get  rid 
of  a  large  amount  of  waste  matter.  In  such  cases,  a  daily 
bath,  especially  in  hot  weather,  is  almost  a  necessity. 

Hot  baths,  with  hot  drinks,  causing  free  sweating,  helped 
on  by  wrapping  the  person  snug  in  bed,  with  a  jug  of  hot 
water  or  a  hot  flatiron  at  the  side  or  feet,  will  often  save 
children  and  others  from  illness,  if  these  measures  are 
promptly  and  vigorously  taken  after  unusual  exposure  to 
cold  or  wet. 

268.  Bathing  in  Cold  Water.     Most   persons,  especially 
the  young  and  vigorous,  soon  get  used  to  cool,  and  even 
cold,  baths.     If,  however,  we  shiver  after  a  bath  instead 
of  feeling  a  warm,  comfortable  glow,  warmer  water  should 
be  used. 

The  first  effect  of  any  cold  bath  is  to  cause  contraction  of 
the  vessels  of  the  skin,  and  make  the  surface  pallid.  Brisk 
rubbing  should  soon  bring  on  a  reaction,  as  it  is  called,  in 
which  the  skin  becomes  red  and  full  of  blood.  Always 


200  OUR   BODIES  AND   HOW  WE   LIVE 

stop  bathing  if  shivering  comes  on,  and  use  the  towel 
vigorously  until  a  feeling  of  genial  warmth  is  felt  all  over 
the  person. 

Young  children  and  old  people,  unless  strong,  vigorous, 
and  well  used  to  it,  cannot  take  a  cold  bath  without  some 
risk.  Like  all  other  things,  bathing  may  be  weakening  if 
carried  to  excess.  Very  much  depends  upon  a  person's 
occupation  and  the  condition  of  the  skin.1 

269.  The  Care  of  the  Hair.     It  adds  to  our  health  and 
comfort  to  keep  the  hair  clean.      The  oil  glands  become 
clogged,  and  dust  and  dirt,  rapidly  making  a  coating  on  the 
scalp,  get  entangled  in  the  hair.     Hence  the  hair  should 
be  washed,   combed,   and  brushed,   often   and  well.     An 
occasional   shampoo  at   home,  with  a  wash  made  of  the 
white  of  an  egg  and  soapsuds,  is  healthful.     Even  a  little 
borax  dissolved  in  plain  water,  with  vigorous  rubbing,  will 
do  much  to  keep  the  scalp  clean  and  healthy. 

270.  Dangers  from  Change  of  "Clothing.     Clothes  serve 
to  keep  up  an  even  temperature  about  the  surface  of  the 

1  Certain  precautions  are  advisable  for  all  who  bathe  in  the  sea.  In  the 
first  place,  bathing  should  never  be  indulged  in  when  one  is  overheated,  nor 
within  two  hours  after  a  hearty  meal.  On  the  other  hand,  bathing  on  a 
perfectly  empty  stomach,  as  before  breakfast,  is  not  advisable ;  it  is  a  good 
plan  for  early  morning  bathers  to  take  a  light  lunch  before  starting  for 
the  beach. 

The  time  of  staying  in  the  water  must  depend  upon  the  individual; 
some  people  can  stay  in  fifteen  or  twrenty  minutes  without  ill  effect,  but 
for  most  people  a  five-minute  plunge  is  long  enough. 

One  of  the  most  serious  results  from  sea  bathing  is  inflammation  of 
the  ears.  No  one  who  has  a  discharge  from  the  ears  should  ever  bathe 
in  the  sea,  especially  in  the  surf,  and  all  would  do  well  to  stop  the  ears 
with  a  little  plug  of  absorbent  cotton  before  going  into  the  water. 

Many  people  who  cannot  bathe  in  the  sea  are  greatly  benefited  by  the 
sea  air  and  by  taking  sponge  baths,  or  even  tub  baths,  in  salt  water  in  their 
own  rooms  every  morning.  These  baths  should  be  followed  by  brisk 
rubbing  with  a  rough  towel. 


THE   SKIN   AND   THE   KIDNEYS  2OI 

body.  In  winter,  they  keep  in  the  bodily  heat  and  protect 
us  from  cold.  In  summer,  they  shield  us  from  the  direct 
rays  of  the  sun. 

Clothes  should  be  changed  according  to  the  climate  or 
time  of  year.  It  is  not  prudent  to  leave  off  winter  clothing 
too  early  in  the  spring,  for  our  seasons  are  most  uncertain. 
Loosely  woven,  porous  material  should  be  worn  next  to  the 
skin,  whether  in  summer  or  winter. 

We  should  never  allow  ourselves  to  feel  cold.  If  we 
cannot  go  where  it  is  warm,  or  put  on  warm  clothing,  we 
should  exercise  until  we  feel  warm. 

271.  Hints  on  the  Use  of  Clothing.     To  keep  our  persons 
sweet  and  clean,  we  must  change  our  clothes  often.     This 
not  only  applies  to  gafments  used  for  daily  wear,  but  to 
bedclothes  and  night  clothes.     No  one  should  sleep  in  the 
clothes  he  wears  during  the  day.     Under-garments  should 
be  frequently  and  regularly  changed.     All  bedclothes  should 
be  exposed  freely  to  the  light  and  the  air. 

Young  children  are  less  able  to  resist  cold  and  sudden 
changes  than  grown-up  people,  hence  great  care  must  be 
taken  with  their  clothing.  The  legs  and  chests  of  children 
should  not  be  unduly  exposed  to  the  bitter  blasts  of  winter 
nor  the  cold  east  winds  of  spring.  Many  children  die  every 
year  from  lung  diseases  due  to  ignorance  or  neglect  in  this 
matter. 

272.  Plain  Advice  on  the  Use  of  Clothing.  -  Never  wear 
wet  or  damp  clothes  longer  than  is  necessary.     If  you  have 
on  wet  clothes,  take  the  shortest  way  home,  rub  down  thor- 
oughly, and  put  on  dry,  warm  garments. 

Do  not  let  your  damp  skirts,  underclothing,  wet  stock- 
ings or  shoes  dry  on  you,  but  always  change  them  at  once 
if  possible.  Neglect  of  this  precaution  is  a  fruitful  cause 


202  OUR   BODIES   AND    HOW   WE    LIVE 

of  rheumatism,  neuralgia,  and  chest  ailments,  especially 
among  young  people  who  are  careless,  ignorant,  or  indif- 
ferent in  matters  of  health. 

Do  not  wear  the  clothing  too  tight,  and  thus  allow  it 
to  interfere  with  free  movements  and  easy,  graceful  car- 
riage, to  say  nothing  of  health.  The  improper  use  of 
corsets  often  crowds  important  organs  out  of  place  and 
retards  their  growth.  Garters  worn  below  the  knee  are 
apt  to  hinder  the  circulation,  and  cause  cold  feet  and 
sometimes  enlarged  veins.1 

273.  Additional  Hints  on  the  Use  of  Clothing.  Dresses 
and  skirts  should  never  drag  their  full  weight  from  the 
hips,  but  should  be  partly  supported  from  the  shoulders. 
Health  and  comfort  should  not  be  sacrificed  to  a  desire  to 
dress  in  a  slavish  submission  to  fashion. 

Children,  and  older  people  too,  should  never  run  out- 
doors without  proper  covering  for  the  head.  Pupils  should 
not  be  allowed  to  sit  in  the  schoolroom  with  outside  gar- 
ments on,  such  as  scarfs,  coats,  rubbers,  and  leggings. 

1  Many  people,  otherwise  neat  in  matters  concerning  their  personal  health, 
will  come  in  from  a  long,  hot,  and  dusty  journey,  remove  a  warm,  perspira- 
tion-soaked dress  or  coat,  and  hang  it  at  once  in  a  close,  dark  closet,  or 
place  in  the  same  receptacle  a  skirt  that  has  been  for  hours  gathering  up 
the  filthy  sweepings  of  streets  and  cars.  It  is  no  wonder  that  the  average 
wardrobe  should  give  out  a  most  disagreeable  odor  when  the  door  has 
been  closed  for  a  short  time. 

All  outer  clothing,  especially  if  of  woolen  material,  should  be  hung  up 
in  a  current  of  fresh  air  to  dry  and  cool  before  being  put  away.  Dress 
shields,  the  linings  of  women's  collars,  and  the  bindings  of  skirts  should  be 
often  renewed. 

The  habit  of  giving  a  hasty  brush  to  the  bottom  of  a  skirt  in  the  house 
—  too  often  in  the  bedroom  —  is  uncleanly  and  may  be  dangerous.  Skirts, 
even  when  they  are  not  allowed  to  sweep  the  pavements,  cannot  fail  to  be 
laden  with  dust  mixed  with  bacteria  which  may  cause  disease.  The  same 
thing  is  true,  to  a  less  degree,  of  other  garments. 


THE    SKIN   AND   THE   KIDNEYS  203 

THE    KIDNEYS 

274.  Getting   rid  of  Waste  Matters.     Our   bodies  are 
never  the  same  for  a  single  moment.     With  every  breath 
and  with  every  beat  of  the  heart  they  are  ever  changing. 
Wear  and  waste  vie  with  growth  and  repair. 

We  eat  food  to  supply  the  bodily  engine  with  fuel,  and 
breathe  in  oxygen  to  feed  the  furnace  fire.  With  a  steady 
burning,  but  without  light,  this  engine  produces  not  only 
motion  and  heat,  but  uses  a  part  of  its  own  energy  to  make 
its  own  repairs.  Not  this  alone,  but  it  even  gets  rid  of 
its  own  soot  and  ashes,  which  would  otherwise  clog  the 
machinery,  and  finally  stop  it. 

We  have  already  learned  that  the  ceaseless  blood  current 
which  carries  fresh  fuel  to  the  tissues,  in  the  shape  of  the 
nutrient  part  of  food,  is  also  a  kind  of  sewer  stream  that 
rids  them  of  waste  matters. 

In  other  words,  the  blood  is  ever  being  made  rich  by 
some  things,  and  is  ever  getting  rid  of  other  things.  The 
blood  carries  fuel  to  the  tissues  of  the  body.  In  the  tis- 
sues a  slow  burning,  or  oxidation,  takes  place  :  the  waste 
or  ashes  must  be  got  rid  of. 

275.  Principal  Waste  Matters  of  the  Body.    What   are 
these  waste  matters  ?     If  we  take  a  piece  of  beef,  dry  it, 
and  burn  it,  we  shall  find  that  it  is  changed  into  four  things, 
—  water,  carbon  dioxide,  ammonia,  and  ashes.     Now,  this 
slow  burning  of  our  tissues  is  really  the  same  thing. 

Hence,  in  whatever  way  our  bodies  are  burned,  or  oxi- 
dized, —  whether  consumed  in*  a  furnace  or  buried  in  the 
ground,  or  oxidized  while  they  are  living,  —  the  end  is 
always  the  same :  water,  carbon  dioxide,  a  kind  of  ammonia 
called  urea,  and  a  small  quantity  of  salts,  or  ashes. 


204  OUR   BODIES   AND   HOW   WE    LIVE 

276.  The  Waste  Matters  described.     Besides  the  water 
which  comes  from  the  food  we  eat,  we  drink  a  great  deal 
of  it  as  plain  water.     We  need  to  keep  the  tissues  continu- 
ally moist  to  help  to  dissolve  the  food,  and  also  to  flush 
them  and  cleanse  them  of  their  useless  matters  and  impu- 
rities.    As  we  wash  the  surface  of  the  body  to  keep  it 
clean,  so  nature  is  ever  bathing  our  tissues  to  wash  away 
their  impurities. 

The  red  blood  corpuscles,  as  we  know,  are  the  tiny  boats 
which  carry  the  oxygen  breathed  in  by  the  lungs  along  the 
blood  stream  to  every  tissue.  The  tissues  contain  carbon, 
which  in  some  mysterious  way  unites  with  the  oxygen, 
forming  carbon  dioxide. 

The  tissues,  especially  the  muscles,  yield  nitrogen.  A 
compound  of  nitrogen,  called  urea,  is  filtered  out  of  the 
body,  through  the  kidneys.  It  is  a  peculiar  substance, 
something  like  ammonia  only  more  complex. 

277.  The  Chief  Organs  of  Excretion.     The  process  by 
which  the  body  gets  rid  of  its  waste  material  is  called 
excretion,  meaning  separation  from,  or  sifting  out. 

The  chief  organs  of  excretion,  or  the  three  main  channels 
by  which  the  waste  products  leave  the  body,  are  the  skin, 
the  lungs,  and  the  kidneys. 

The  functions  of  these  three  organs  are  closely  allied. 
They  differ  very  much  in  appearance,  but  are  built  on  the 
same  general  principle.  The  blood,  as  it  passes  through 
the  numberless  capillaries  in  these  organs,  is  purified  by  a 
sifting  process.  The  waste  matters  are,  as  it  were,  sifted 
from  the  blood,  and  finally  removed  from  the  body. 

The  structure  of  the  skin  has  already  been  described. 
One  function  of  the  skin,  as  we  have  seen,  is  to  rid  the 
body  of  water  and  other  matters  in  the  form  of  sweat. 


THE   SKIN   AND   THE    KIDNEYS 


205 


FIG.  128.     Vertical  Section  of  the  Back.      (Posterior  view.) 

The  spinal  column  below  the  twelfth  dorsal  vertebra  at  A  has  been  removed,  as 
well  as  the  various  layers  of  the  great  muscles  of  the  back.  The  two  kid- 
neys with  the  renal  arteries  and  veins  are  plainly  shown,  in  their  normal 
positions.  The  relative  positions  of  adjacent  vessels  and  organs  with  their 
names  printed  upon  them  are  also  shown.  B,  portion  of  the  diaphragm  on 
the  left  side;  C,  receptaculum  chyli;  Z>,  a  part  of  the  small  intestine  on 
the  left  side. 


206  OUR  BODIES   AND   HOW  WE    LIVE 

The  lungs  have  also  been  described  in  a  previous  chapter. 
One  duty  of  the  lungs,  as  we  have  learned,  is  to  excrete  carbon 
dioxide,  watery  vapor,  and  a  small  quantity  of  other  wastes. 

278.  The  Kidneys.     The  kidneys,  two  important  organs 
of  excretion,  are  of  a  brownish-red  color,  about  four  inches 
long  and  two  inches  wide,  and  of  the  shape  of  a  kidney 
bean.     They  lie  in  the  region  of  the  loins,  in  front  of  the 
backbone,  behind  the  intestines,  one  on  each  side,  and  are 
imbedded  in  fat.     A  sheep's  kidney  is  a  familiar  sight  in  a 
market.     It  is  very  much  like  the  same  organ  in  man. 

279.  The  Structure  of  the  Kidneys.     The   kidneys  are 
made  up  of  bundles  of  long  tubes,  not  so  very  unlike  sweat 
glands.     These  tubes  are  surrounded  by  a  meshwork  of 
capillaries.     They  are  very  fine,  threadlike  structures,  not 
more  than  a  five-hundredth  of  an  inch  in  diameter.     Thus, 
there  are  thousands  upon  thousands  of  them  packed  together 
in  each  kidney. 

The  blood  filters  certain  waste  matters  dissolved  in 
water  into  these  tubes,  just  as  it  gives  up  sweat  to  the 
sweat  glands.  These  tubes  unite  into  one  common  duct 
from  each  kidney,  which  carries  away  the  excretion.  In 
due  time  this  waste  material  is  cast  out  of  the  body. 

The  kidneys  thus  serve  as  a  peculiar  and  delicate  kind 
of  filter,  carrying  off  urea,  inorganic  salts,  and  other  waste 
matters  dissolved  in  a  large  quantity  of  water.1 

280.  The  Work  done  by  the  Kidneys.    About  three  pints 
of  fluid  are  daily  discharged,  on  an  average,  through  the 

1  The  whole  of  this  excretion  is  called  the  urine.  It  is  in  reality  water, 
holding  in  solution  urea  and  several  salts.  The  urine  is  constantly  being 
secreted  by  the  kidneys.  It  is  carried  to  the  bladder,  which  serves  as  a 
reservoir.  It  collects  in  the  bladder  until  this  receptacle  is  nearly  full, 
when  it  is  emptied  by  the  contraction  of  its  walls,  aided  by  the  abdominal 
muscles. 


THE    SKIN   AND    THE   KIDNEYS 


207 


kidneys,  and  a  little  over  one  ounce  of  urea.  Out  of  the  body, 
the  urea  soon  changes  into  carbon  dioxide  and  ammonia. 

Besides  urea,  the  kidneys  also  serve  to  carry  off  each 
day  almost  an  ounce  of  various  mineral  substances  that  are 
either  foreign  to  the  body  or 
are  present  in  the  blood  in  too 
large  a  proportion,  —  for  ex- 
ample, common  salt. 

If  the  kidneys  are  inactive 
or  fail  to  excrete  the  nitroge- 
nous waste  matters,  the  work 
of  many  other  organs  is  seri- 
ously impaired.  The  blood 
is  poisoned,  and  death  may 
result  from  the  poisonous 
material  which  is  retained  in 
the  tissues. 

281.  The  Health  of  the  Kid- 
neys. The  kidneys  are  very 
busy  organs.  Their  health  is 
a  matter  of  prime  importance. 

We   have   already  become 
familiar  with  the  hygiene  of 
two  great  organs  of  excretion, 
—  the  skin  and  the  lungs. 

These  three  sets  of  organs, 
working  together  in  harmony, 

like  three  groups  of  mechanics  doing  some  difficult  work, 
keep  the  bodily  machinery  from  getting  clogged  and  choked 
with  waste  matters. 

If  the  free  action  of  the  skin  or  the  lungs  is  interrupted, 
the  kidneys  have  extra  work  to  do.     They  make  every  effort 


FIG.  129.    Vertical  Section  of  the 
Kidney. 

A,  pyramids  of  the  kidney ;  B,  apices, 
or  papillae,  of  the  pyramids ;  C,  pel- 
vis of  the  kidney;  JD,  upper  end  of 
ureter. 


208  OUR   BODIES   AND   HOW  WE   LIVE 

to  do  the  additional  work  that  is  thrown  upon  them  ;  but, 
sooner  or  later,  they  fail  under  the  burden,  and  become 
diseased. 

282.  Effect  of  Alcohol  upon  the  Skin.  As  we  have 
already  learned  in  previous  sections,  the  paralyzing  action 
of  alcohol  results  in  a  dilatation  of  the  arteries  and  the  capil- 
laries. Now,  it  is  evident  that  the  skin,  like  any  other  active 
organ,  depends  for  its  nourishment  upon  the  proper  circu- 
lation of  the  blood.  Hence,  if  this  circulation  is  interfered 
with,  the  skin  lacks  its  chief  element  of  vitality. 

The  flushed  and  warm  face,  so  often  noticed  after  taking 
a  very  moderate  amount  of  alcoholic  liquor,  is  due  to  the 
temporary  dilatation  of  the  capillaries  in  the  skin.  If  the 
use  of  alcoholic  beverages  is  continued  for  a  long  period, 
this  dilatation  of  the  blood  vessels  becomes  permanent.  The 
tiny  capillaries  about  the  face  are  often  seen  running  their 
crooked  course  just  under  the  skin  of  the  nose  and  the 
cheeks. 

The  skin,  as  we  know,  is  the  chief  regulator  of  the  loss 
of  heat  from  the  body.  When  we  drink  alcoholic  liquors, 
more  blood  is  carried  to  the  surface  and  more  heat  passes 
by  radiation  from  the  skin  into  the  cold  air.  Thus,  heat 
which  is  needed  elsewhere,  especially  in  cold  weather,  is 
lost.  In  other  words,  the  surface  of  the  body  is  warmed 
at  the  expense  of  its  vital  organs  within. 

The  skin  also  plays  an  important  part  in  the  excretion 
of  waste  matters.  If  the  circulation  of  the  skin  is  dis- 
turbed, as  it  is  by  alcohol,  so  that  it  is  unable  to  do  its 
portion  of  work  in  the  process  of  excretion,  more  work  is 
required  of  the  kidneys.  These  important  organs  are  then 
overworked,  resulting  in  more  or  less  disturbance  of  the 
general  health. 


THE   SKIN    AND   THE    KIDNEYS  209 

283.  Effects  of  Alcohol  upon  the  Kidneys.  The  kidneys 
differ  from  some  other  organs  which  can  rest  awhile 
without  any  harm  to  the  body.  For  instance,  we  can 
keep  the  eyes  closed  for  a  few  days,  if  necessary,  without 
injury,  and  in  fact  often  with  benefit ;  or,  we  can  abstain 
from  food  for  some  days,  if  need  be,  and  let  the  stomach 
rest.  But  the  kidneys  cannot,  with  safety,  cease  their 
work  even  for  one  hour.  Their  duty  in  ridding  the  blood 
of  waste  products  and  of  any  foreign  or  poisonous  mate- 
rial introduced,  must  be  done  continually,  or  the  general 
health  of  the  whole  body  is  disturbed. 

Thus  it  is,  as  we  may  well  suppose,  that  these  two  impor- 
tant organs,  with  their  large  blood  vessels  conveying  enor- 
mous amounts  of  blood  to  and  from  their  tissues,  feel  very 
quickly  the  presence  of  alcohol.  Alcoholic  liquors  tend 
to  irritate  the  delicate  kidney  tissues  and  thus  speedily 
disturb  their  work  of  excreting  the  waste  materials  from 
the  blood. 

The  continued  congestion  of  the  kidneys  may  result  in 
a  series  of  disturbances  from  the  imperfect  elimination 
of  waste  matter.  The  urea,  which  is  a  poison  and  which 
must  be  removed,  may  be  retained  in  the  system,  while 
the  albumin,  which  is  essential  to  healthy  blood,  may  be 
filtered  away  through  the  overtaxed  kidneys.- 

The  long-continued  use  of  alcohol  may  produce  such  a 
change  in  the  structure  of  the  kidneys  that  fat  cells  become 
infiltrated  into  the  tissues,  causing  in  them  what  is  known 
as  fatty  degeneration. 


210  OUR   BODIES   AND    HOW  WE   LIVE 


QUESTIONS  ON  THE  TEXT 

I.  Give  a  general  definition  of  the  skin.     2.  What  purpose  does 
the   skin  serve?     3.   Of    what   two   layers    is    the    skin    composed? 
4.  Describe  in  some  detail  the  scarfskin.     5.  What  gives  the  color 
to  the  skin?     6.  Describe  briefly  the  dermis,  or  true  skin.     7.  What 
are  the  papillae  ?     8.  How  may  the  skin  absorb  various  kinds  of  poi- 
son?    9.  Give  some  of  the  more  common  ways  in  which  the  absorp- 
tion of  poisons  by  the  skin  may  take  place.     10.  Describe  the  structure 
of  a  hair. 

II.  How  does  the  hair  grow?     12.  What  gives  the  color  to  the 
hair?     13.  Describe  the  muscles  with  which  the  skin  is  provided. 
14.  What   are   the   nails?     15.   Describe  the  structure   of  the  nails. 
16.  Give  some  practical  points  about  the  care  of  the  nails.    17.  What 
are  oil  glands  ?    18.  What  purpose  do  the  oil  glands  serve  ?     19.  In 
what  parts  of  the  skin  are  the  oil  glands  found  ?     20.  Describe  the 
sweat  glands. 

21.  What  is  sweat,  or  perspiration?  22.  What  is  the  most  impor- 
tant function  of  the  perspiration  ?  23.  Explain  in  some  detail  why  we 
should  take  proper  care  of  the  skin.  24.  For  what  two  reasons  are 
baths  taken?  25.  Give  some  practical  hints  about  bathing  in  cold 
water.  26.  Why  should  we  take  good  care  of  the  hair?  27.  What 
useful  purpose  do  our  clothes  serve  ?  28.  Give  a  few  practical 
points  on  the  use  of  clothing.  29.  What  plain  advice  can  you  give 
about  clothing?  30.  What  other  points  about  clothing  have  you 
learned  from  the  text  ? 

31.  Explain  briefly  how  our  bodies  get  rid  of  waste  matters. 
32.  What  part  does  the  blood  play  in  these  changes?  33.  What  are 
the  chief  waste  matters  of  the  body?  34.  What  is  meant  by  excre- 
tion? 35.  What  are  the  three  chief  organs  of  excretion?  36.  What 
do  the  skin  and  the  lungs  excrete?  37.  What  are  the  kidneys? 
38.  Describe  the  structure  of  the  kidneys.  39.  What  can  you  say 
of  the  work  done  by  the  kidneys?  40.  Show  how  the  three  great 
organs  of  excretion  should  work  in  harmony.  41.  Give  briefly  the 
effect  of  alcohol  upon  the  skin.  42.  What  is  the  effect  of  alcoholic 
liquors  upon  the  kidneys  ? 


CHAPTER  X 
THE  NERVOUS  SYSTEM 

284.  All  Parts  of  the  Body  work  together  in  Harmony. 
In  the  preceding  chapters,  we  have  learned  that  each  organ 
not  only  looks  after  itself,  but  is  ever  ready  to  come  to  the 
help  of  other  parts  of  the  body.     Everywhere  we  find  organs 
working  together  for  each  other's  good.    Strike  suddenly  at 
the  eye,  and  the  lids  fall  to  protect  it.    Tickle  the  foot,  and 
the  muscles  of  the  leg  contract  and  pull  it  away.    When  the 
skin  is  inactive,  the  kidneys  come  to  its  help. 

Fifty  skilled  mechanics  might  do  their  best  at  building 
a  vessel  or  a  house,  but  if  each  man  worked  as  he  pleased, 
and  took  no  heed  of  the  rest,  the  result  of  their  work  would 
be  of  little  account.  The  master  builder  must  be  at  his 
post,  skillful  to  direct  and  quick  to  act.  So  it  is  with  our 
bodies.  The  wonderful  agency  which  governs  every  organ 
of  the  body  is  the  nervous  system. 

285.  The  Nervous   System  compared  to  a  Telegraphic 
System.     The  nervous  system  may  be  aptly  compared  to 
a  complete  telegraphic  system.     The  brain  and  the  spinal 
cord  are  the  main  offices;  and  the  nerves,  branching  off 
to  all  parts  of  the  body,  are  the  telegraph   wires.     The 
brain  and  the  spinal  cord  together  are  called  the  cerebro- 
spinal  center.     Dispatches  are  constantly  being  sent  to  the 
cerebro-spinal  center  to  inform  it  of  what  is  going  on  in 
various  parts  of  the  body.     The  cerebro-spinal  center,  on 


212 


OUR   BODIES   AND   HOW   WE   LIVE 


receiving  the  news,  at  once  sends  back  its  commands  as  to 
what  must  be  done.  In  brief,  countless  dispatches  are  sent 
to  and  fro  with  wonderful  rapidity  and  unerring  precision. 

Thus,  if  we  accidentally  pick  up  a  hot  coal,  we  drop  it 
instantly.  A  nervous  impulse  or  message  is  sent  from  the 
nerves  of  touch  in  the  fingers  to  the  cerebro- 
spinal  center,  which  hurries  off  its  orders  to 
the  muscles  of  the  fingers  to  drop  the  burn- 
ing coal. 

286.  Nerve  Cells  and  Fibers.     Nerve  tissue 
is  really  made  up  of  a  great  number  of  distinct 
units    called   nerve   cells.      Each    cell   usually 
contains  a  large  nucleus  and  gives  off  one  or 
FIG.  130.       more  tiny  branches,  or  processes.    These  cells 
Nerve  Cells    vary  more  in  shape  and  size  than  any  other 

Cdls    ln    the    b°dy-        Each    nei"Ve    Cdl    haS    a 

number  of  short  branches,  and  many  have 
also  one  long  branch  which  can  be  traced  for  some  distance 
from  the  cell  body.  This  rootlike  process  is  called  an  axis 
cylinder.  This  is  the  beginning 
of  a  nerve  fiber. 

In  most  fibers  a  layer  of 
white,  fatty  substance,  called 
the  medullary  sheath,  protects 
this  soft,  gray  central  core,  the 
axis  cylinder,  as  a  kind  of  insu- 
lating material,  just  as  electric 
wires  are  sometimes  covered 
with  waxed  paper  or  thread  to 
prevent  the  escape  of  the  current.  Outside  of  this  is 
another  transparent  sheath,  or  covering,  called  the  neuri- 
lemma.  Some  fibers  lack  the  white  medullary  sheath. 


FIG.  131.     Nerve  Cells  from  the 
Gray  Matter  of  the  Brain. 


THE   NERVOUS    SYSTEM 


213 


Nerve  fibers  may  be  only  the  smallest  fraction  of  an 
inch  in  length,  or  they  may  be  several  feet  long.  Thus, 
there  are  nerve  fibers  which  run  from  the  spinal  cord  to 
the  tips  of  the  toes.  The  axis  cylinders  end  in  branches 
running  to  muscle  fibers,  to  glands,  or  they  may  end  in 
contact  with  sense  cells  in  a  sense  organ. 

Wherever  the  nerve  cells  are  abundant,  the  nerve  tissue 
has  a  gray  color ;  in  other  places,  it  looks  white.  Most 
of  the  gray  matter  of  the  brain  is  on  the  surface.  In  the 
spinal  cord,  the  gray 
matter  lies  within  the 
white  matter,  pre- 
senting, in  section,  a 
crude  outline  of  the 
letter  H  (Fig.  140). 

287.  Work  done  by 
Nerve  Cells  and  Nerve 
Fibers.  The  nerve 
cells  are  highly  active 
masses  of  living  matter  which  are  nourished  by  material 
brought  to  them  by  the  blood. 

The  nerve  fibers  are  conductors  of  nervous  impulses  or 
messages.  They  serve,  not  unlike  telegraph  wires,  to  con- 
nect remote  parts  of  the  body  with  central  nerve  stations. 

Experiment  64.  To  show  the  structure  of  the  nerves.  Take  a 
small  piece  of  a  nerve,  which  may  be  easily  obtained  from  the 
market.  Tease  it  lengthwise  with  needles  on  a  glass  slide.  With 
a  hand  lens,  or  even  with  the  naked  eye,  the  nerve  is  seen  to  be 
made  up  of  silky  threads. 

Take  one  of  the  threads  and  fray  it  out  as  finely  as  possible  on  a 
clean  slide.  Add  a  drop  of  saline  solution,  and  examine  under  the 
high  power  of  the  microscope.  The  nerve  fibers  are  now  seen  as 
exceedingly  slender,  white  threads  with  a  well-marked  wavy  outline. 


FIG.  132.     Portion  of  a  Medullated 
Nerve  Fiber. 

The  axis  cylinder  is  in  the  center.  On  either  side 
is  seen  the  medullary  sheath,  represented  by 
dark  lines.  The  primitive  sheath,  or  neuri- 
lemma,  is  on  the  outside  and  represented  by 
white  lines  in  which  is  a  nerve  corpuscle  with 
an  oval  nucleus. 


2I4 


OUR   BODIES   AND   HOW  WE   LIVE 


FIG.  133.     Diagram  of  a 
Neuron,  or  Nerve  Unit. 

Showing  a  motor  cell  with  its 
long,  unbranched  process 
(with  two  little  lateral  off- 
shoots), with  motor  endings 
in  striated,  voluntary  mus- 
cular tissue. 


288.  Structure  of  the  Nerves.     If 
we  take  a  small  piece  of  a  nerve  from 
a  dead  rabbit  or  frog,  and  with  needles 
separate  it   lengthwise   on   a   glass 
slide,  we  find  it  can  be  pulled  apart 
into  bundles  of   silky  threads.      If 
these  threads  are  frayed  out  as  finely 
as  possible,  the  high  power  of  the 
microscope    reveals    still    smaller 
threads  or  fibers.      It  would   take 
about    four   thousand   average-sized 
nerve  fibers  to  cover  an  inch  when 
placed  side  by  side. 

The  nerve  fibers  bound  together 
in  cords  of  various  sizes  form  the 
nerves. 

289.  General  Arrangement  of  the 
Nervous  System.    The  nervous  sys- 
tem consists  of  two  great  sets  of 
nerves  and  nerve  centers  which  are 
intimately  related,  and  yet  for  con- 
venience may  be  studied  apart. 

These  are  the  cerebro-spinal  system 
and  the  sympathetic  system. 

The  cerebro-spinal,  or  central  nerv- 
ous, system  consists  of  the  brain  and 
the  spinal  cord,  together  with  the  nerves 
which  branch  off  from  each. 

The  sympathetic  system  consists 
chiefly  of  a  double  chain  of  ganglia, 
or  knots  of  nerve  cells,  lying  at 
the  sides  and  in  front  of  the  spinal 


THE   NERVOUS   SYSTEM 


2I5 


column,  and  connected  with  one  another  and  with  the 
central  nervous  system  by  nerve  fibers  (Sec.  304). 

290.  The  Brain.     The  brain  fills  the  entire  cavity  of  the 
skull,  and  consists  of  a  number  of  separate  masses  of  nerve 
matter  abundantly  supplied 

with  blood  vessels  (Fig.  98). 

The  brain  is  the  organ  of 
the  mind;  in  other  words, 
it  is  the  seat  of  con- 
sciousness, the  intellect, 
the  memory,  the  will,  the 
affections,  the  emotions, 
and  sensation. 

The  brain  controls  all 
voluntary  motions. 

291.  The  Weight  of  the 
Brain.   The  average  weight 
of  the  human  brain  is  about 
fifty  ounces,  or  about  three 
pounds.1    A  few  cases  have 

1  The  brain  of  Oliver  Cromwell 
is  said  to  have  weighed  eighty 
ounces.  Daniel  Webster's  brain 
weighed  fifty-three  and  a  half 
ounces,  and  Ruloff's  —  a  notorious 
murderer,  but  in  some  respects  a 
very  learned  man  —  fifty-nine 
ounces.  The  brain  of  Cuvier,  the 
celebrated  naturalist,  weighed 
sixty-four  and  a  third  ounces ;  and 
that  of  Dupuytren,  a  famous 
French  surgeon,  sixty-two  and  a 

half  ounces.  The  hats  of  ten  gentlemen  were  tried  upon  the  skull  of  Robert 
Burns,  and  the  only  one  of  the  ten  that  could  cover  it  was  the  hat  of  Thomas 
Carlyle.  An  idiot's  brain  is  usually  small,  rarely  exceeding  thirty  ounces. 


FIG.  134.  Diagram  illustrating  the 
General  Arrangement  of  the  Nerv- 
ous System.  (Posterior  view.) 


216 


OUR  BODIES   AND    HOW  WE   LIVE 


been  noted  in  men  of  great  mental  capacity,  in  which  the 
brain  weighed  sixty-four  ounces.  As  a  rule,  a  large  brain 
stands  for  a  vigorous  mind  and  superior  faculties. 

The  brain  and  head  in  a  child  are  very  large  in  propor- 
tion to  the  rest  of  the  body.  The  brain  grows  very  rapidly 
until  the  fifth  year,  then  very  slowly,  and  after  twenty  the 

growth  is  not  per- 
ceptible. 

292.  The  Three 
Parts  of  the  Brain. 
The  three  princi- 
pal masses    or 
parts  which  make 
up  the  brain  are: 

(1)  the  cerebrum, 
or  brain  proper ; 

(2)  the  cerebellum, 
or  lesser   brain  ; 

(3)  the  medulla  ob- 
longata. 

293.  The  Cere- 
brum.    The  cere- 
brum fills    the 
whole  of  the  up- 
per  part    of    the 
skull,  and  is  nearly 
seven  eighths  of 

the  entire  mass.  It  consists  of  two  parts,  or  halves,  almost 
separated  from  each  other  by  a  deep  cleft,  or  fissure,  from 
front  to  back.  Each  of  these  halves  —  or  hemispheres,  as 
they  are  called  —  consists  of  three  portions,  or  lobes,  so 
that  the  cerebrum  is  made  up  of  six  distinct  parts. 


FIG.  135.     The  Upper  Surface  of  the  Cerebrum. 

Showing  its  division  into  two  hemispheres, 
and  also  the  convolutions. 


THE   NERVOUS   SYSTEM 


217 


294.  The  Convolutions  of  the  Cerebrum.  The  cerebrum 
has  a  peculiar  folded-up  appearance,  its  various  folds  —  or 
convolutions,  as  they  are  called  —  being  separated  by  deep 


FIG.  136.     The  Left  Half  of  a  Vertical  Median  Section  of  the  Brain. 

A,  frontal  lobe  of  the  cerebrum ;  B,  parietal  lobe ;  C,  parieto-occipital  lobe ; 
D,  occipital  lobe ;  E,  cerebellum ;  F,  arbor  vitae ;  H,  pons  Varolii ;  A",  me- 
dulla oblongata. 

clefts,  sometimes  nearly  an  inch  deep.  In  this  simple  way 
the  surface  of  the  brain  is  increased  many  fold.  The  cere- 
brum is  made  up  of  both  white  and  gray  matter. 

The  interior  of  the  brain  is  made  up  chiefly  of  the 
white  nerve  substance  just  spoken  of,  and  also  important 
masses  of  gray  matter  called  ganglia.  The  gray  matter  is 
the  outer  layer,  about  one  eighth  of  an  inch  in  thickness, 
and  is  spread  over  the  white  substance  somewhat  like  a 
silk  handkerchief  which  has  been  crumpled  up. 


218  OUR   BODIES   AND   HOW  WE   LIVE 

The  active  powers  of  the  mind  are  supposed  to  reside  in 
this  outer  layer  of  the  brain.  These  powers  are  great  or 
small,  according  to  the  number  and  the  extent  of  its  folds, 
or  convolutions.  In  the  lowest  vertebrate  animals  the  brain 
has  no  folds  ;  but  as  we  pass  to  animals  of  a  higher  grade, 
the  folds  begin  to  appear.1 

295.  The  Cerebellum.     The  cerebellum,  or  little  brain,  lies 
beneath  the  back  part  of  the  brain  proper.     It  is  made  up 
of  two  halves,  each  formed  of  a  number  of  layers  of  gray 
and  white  nerve  matter,  curiously  arranged.    These  masses 
resemble  somewhat,  in  section,  the  branches  of  a  tiny  tree 
and  hence  are  fancifully  called  "arbor  vitas  "  (Fig.  136). 

The  functions  of  the  cerebellum  are  not  yet  certainly 
known.  It  appears  to  aid  in  the  control  of  the  muscles  of 
the  body;  that  is,  it  serves  to  bring  the  various  muscular 
movements  into  harmonious  action. 

296.  The  Medulla  Oblongata.     The  medulla  oblongata  is 
the  thick  continuation  of  the  spinal  cord  lying  within  the 
cavity  of  the  skull.     It  is  just  under  the  little  brain,  and 
makes  the  connecting  link  between  the  brain  and  the  spinal 
cord.     It  is  a  highly  important  part  of  the  brain,  since  from 
it  arise  important  nerves  which  regulate  breathing,  swallow- 
ing, the  heart's  action,  and  other  vital  processes.     If  this 
part  of  the  brain  be  broken  or  cut,  respiration  and  circula- 
tion will  at  once  cease,  causing  instant  death. 

1  The  brain  is  inclosed  within  three  distinct  membranes,  —  the  dura 
mater  (hard  mother),  the  arachnoid  (like  a  spider's  web),  and  the  pia 
mater  (delicate  mother). 

The  dura  mater  is  the  tough  membrane  which  lines  the  inner  surface  of 
the  skull  and  forms  a  loose  outer  covering  for  the  brain.  The  middle 
layer,  called  the  arachnoid,  secretes  a  fluid  which  keeps  the  inner  surface 
moist.  The  pia  mater  is  a  very  delicate  membrane  which  dips  down  between 
the  folds  of  the  cerebrum. 


THE    NERVOUS    SYSTEM 


2I9 


Experiment  65.  To  show  the  brain.  Get  a  sheep's  brain  from  the 
butcher.  Pay  him  to  dissect  away  the  skin  and  muscles  of  the  skull, 
under  your  direc- 
tion, and  to  saw 
open  the  cranium  in 
such  a  manner  as 
to  expose  the  entire 
upper  surface  of  the 
brain.  Remove  the 
sawed  top  and  care- 
fully  tear  off  the 
dura  mater  from 
the  bones. 

Now  cut  away 
enough  of  this  mem- 
brane so  that  the 
sides  of  the  skull 
can  be  sawed  and 
torn  away,  to  allow 
the  brain  to  be  lifted 
out  in  fair  condition. 
Put  all  the  torn  parts 
and  membranes 
back  into  place. 

The  sheep's 
brain  is  very  small 
and  not  to  be  com- 
pared in  size  with 
that  of  a  man,  but 
the  general  arrange- 
ment of  the  parts  is 
the  same. 

Note  the  dura  mater,  the  tough,  outer  membrane ;  the  arachnoid, 
the  thin  membrane  which  lines  the  dura  mater ;  and  the  pia  mater,  the 
delicate  membrane  which  is  closely  attached  to  the  brain.  Find  the 
cerebrum,  or  big  brain ;  the  cerebellum,  or  little  brain  ;  the  medulla, 
and  the  stumps  of  the  cranial  nerves  (Note,  p.  218). 

In  the  cerebellum  examine  the  curious  folded  arrangement  of  the 
gray  and  white  matter  forming  the  arbor  vitae.  Cut  open  the  cerebral 


FIG.  137.     The  Base  of  the  Brain. 

A,  anterior  lobe  of  the  cerebrum ;  B,  olfactory  nerve ; 
C,  portion  of  the  posterior  lobe ;  £>,  optic  chiasm ; 
E,  optic  tract ;  //,  M,  hemispheres  of  the  cerebellum ; 
K,  portion  of  the  occipital  lobe ;  N,  medulla  oblongata  ; 
R,  pons  Varolii.  (See  also  Fig.  98.) 


220 


OUR   BODIES  AND   HOW  WE    LIVE 


v-ist  and  2nd 
'l  Spinal  Nerves 


FIG.  138.     BLACKBOARD  SKETCH. 

Diagram  of  the  Distribution  of 
the  Cranial  Nerves. 

The  cranial  nerves  are  thus  arranged  in  pairs : 

1,  olfactory  nerves,  special  nerves  of  smell; 

2,  optic  nerves,  passing  to  each  eyeball,  de- 
voted to  sight ;  3,  4,  and  6  control  the  muscles 
of  the  eyes;    5,  trifacial  in  three  branches, 
which  proceed  mainly  to  the  face,  partly  sen- 
sory and  partly  motor ;    7,  facial  nerves,  con- 
trolling the  facial  muscles ;    8,  auditory,  or 
nerves  of  hearing,  distributed  to  the  organs 
of  hearing ;  9,  glossopharyngeal  nerves,  partly 
sensory  and  partly  motor:    each  nerve  con- 
tains two  roots,  one  a  nerve  of  taste,  the  other 
a  motor  nerve,  which   controls  the   muscles 
engaged  in   swallowing;    10,   pneumogastric 
nerves    (described   in   Sec.   297);    n,   spinal 
accessory  nerves,  supplying  some  of  the  mus- 
cles of  the  neck  and  back;    12,  hypoglossal 
nerves,   controlling    the    movements    of    the 
tongue  in  speech  and  swallowing. 


hemisphere  andobserve  the 
gray  and  the  white  matter 
inside.  The  brain  should 
be  first  examined  as  a 
whole,  and  compared  with 
the  description  given  in  the 
text,  or  with  the  diagrams 
of  the  human  brain.  With 
careful  dissection  and  by 
comparison  with  diagrams, 
most  of  the  twelve  pairs 
of  cranial  nerves  can  be 
identified. 

NOTE.  —  A  fresh  brain 
is  too  soft  for  handling  or 
for  careful  study.  Hence 
it  should  be  hardened  and 
made  ready  for  use  several 
weeks  before  it  is  needed. 
A  mixture  of  one  fourth  of 
an  ounce  of  bichromate 
of  potash  and  one  ounce 
of  a  forty-per-cent  solu- 
tion of  formalin  to  about 
one  quart  of  water  makes 
a  useful  hardening  and 
preserving  fluid. 

297.  The  Cranial 
Nerves.  From  each 
side  of  the  brain  pro- 
ceed twelve  pairs  of 
nerves,  called  cranial 
nerves.  They  pass  out 
of  the  skull  in  pairs 
through  little  holes  in 
its  base,  and  supply  the 


THE   NERVOUS   SYSTEM 


221 


face,  the  organs  of  smell,  taste,  hearing,  and  sight,  and 
certain  internal  organs.  The  cranial  nerves  are  of  three 
kinds,  —  sensory,  motor,  and  mixed,  i.e.  combining  both. 

The  tenth  pair,  called  the  pneumogastric  or  the  vagus,  the 
"wandering  nerve,"  is  perhaps  the  most  important  nerve 
in  the  body:  It 
supplies  the  larynx, 
the  lungs,  the 
heart,  the  stomach, 
and  the  liver.  It  is 
partly  motor  and 
partly  sensory. 

298.  The  Spinal 
Cord.  The  spinal 
cord  is  a  column  of 
soft  nerve  tissue, 
extending  from  the 
base  of  the  skull  to 
the  region  of  the 
loins,  where  it 
tapers  into  little 
threads.  It  is  a 
continuation  of  the 
medulla  oblongata, 
and  its  average 
length  is  about 

eighteen   inches.  FlG-  T39-     Trunk  of  the  Left  Pneumogastric 

"    -ru  •      i  Nerve. 

Ine  spinal  cord 

Showing  its  distribution  by  its  branches  and  ganglia  to 
!  C  6 1 V  6  S     impres-        the  iarynX)  pharynx,  heart,  lungs,  and  other  parts. 

sions  from  various 

parts  of  the  body  by  means   of  its   sensory  nerves,  and 

carries  them  to  the  brain,  where  they  excite  sensation, 


222  OUR   BODIES   AND    HOW  WE   LIVE 

or  consciousness.     It  also  sends  out,  by  means  of  its  motor 
nerves,  the  commands  of  the  brain  to  the  voluntary  muscles. 

Experiment  66.  To  show  the  spinal  cord.  Get  at  the  market  an 
uninjured  piece  of  the  spine  of  an  ox.  Cut  this  across  with  a  sharp 
knife,  and  examine  it  for  the  following  points.  The  cord  is  clothed 
with  a  vascular  membrane,  the  pia  mater,  and  is  composed  partly  of 
a  white  substance  lying  on  the  outside,  and  partly  of  a  pinkish-gray 
substance  lying  within.  There  are  two  crescentlike  masses  of  gray 
substance  (arranged  roughly  in  the  form  of  an  H),  lying  one  in  each 
half  of  the  cord  and  joined  by  a  narrow  bridge  of  the  same  material, 
which  crosses  the  middle  of  the  cord.  The  white  matter  surrounds 
the  gray  crescents. 

The  cord  is  almost  divided  into  halves  (exactly  similar  to  each 
other)  by  an  anterior  and  posterior  fissure.  In  the  middle  of  the 
bridge  of  gray  matter  there  is  a  little  canal,  called  the  "  central  canal," 
which  runs  the  whole  length  of  the  spinal  cord.  This  canal  cannot, 
however,  be  seen  with  the  naked  eye. 

299.  Reflex  Action  of  the  Cord  and  Brain.  The  spinal 
cord  is  not  merely  a  bundle  of  nerve  fibers  for  carrying 
messages  to  and  from  the  brain.  It  also  acts  as  a  kind  of 
independent  center,  receiving  messages  from  certain  parts 
of  the  body  by  means  of  its  sensory  nerves,  and  on  its 
own  authority  sending  back  orders  to  the  muscles  by  its 
motor  nerves,  without  waiting  to  consult  the  brain.  This 
is  known  as  reflex  action. 

If  one  is  asleep,  and  the  feet  are  gently  tickled,  the  legs 
will  be  moved  out  of  the  way  without  the  sleeper  necessarily 
being  awakened.  When  the  spine  is  broken  by  an  injury, 
causing  pressure  upon  the  cord,  all  sensation  and  motion  are 
lost  in  the  paralyzed  limbs.  But  if  these  paralyzed  limbs 
are  irritated,  as  by  pricking  the  soles  of  the  feet  with  a  needle, 
then  the  legs  kick  out  vigorously.  The  injured  person  does 
not  feel  the  pain  of  the  needle,  and  can  exercise  no  control 
over  the  legs.  There  is  no  conscious  action  whatever. 


THE   NERVOUS    SYSTEM 


223 


This  unconscious  motion  is  the  result  of  reflex  action 
of  the  spinal  cord.  It  is  called  reflex  because  the  impres- 
sion does  not  go  to  the  brain,  but  is  reflected,  meaning 
turned  back  again,  from  the  sensory  nerves  through  the 
motor  nerves. 

300.  Importance  of  Reflex  Action.  We  rarely  stop  to 
think  how  important  reflex  action  is  to  our  health,  comfort, 
and  safety.  Because  we  are  able  to  do  hundreds  of  things 


POSTERIOR 

FIG.  140.     BLACKBOARD  SKETCH. 
Illustrating  the  path  of  a  simple  nervous  reflex  action.* 

every  day  without  any  effort  of  the  will,  we  are  apt  to  for- 
get its  importance.  In  fact,  the  greater  part  of  nerve  power 
expended  in  the  body  goes  to  produce  these  numberless 
reflex  actions. 

1  For  illustration,  let  us  note  what  happens  when  the  tips  of  the  fingers 
are  in  danger  of  being  burnt.  The  organ  of  sensation  in  the  finger  tip 
sends  the  impression  of  pain  along  the  sensory  fibers  (through  the  ganglion) 
of  the  posterior  root  by  means  of  a  long  nerve  branch  to  the  cells  in  the 
posterior  horn  of  the  gray  matter  of  the  spinal  cord.  At  the  cord,  the 
sensation  may  go  to  the  brain,  or  instead  it  may  at  once  pass  to  the  anterior 
horn  of  the  gray  matter  of  the  cord.  Thence  the  impulse  is  sent  forth 
along  the  motor  fibers  to  the  muscles  of  the  arm.  The  muscles  promptly 
contract,  and  the  fingers  are  jerked  away  from  the  irritating  object  even 
before  the  brain  knows  what  is  taking  place. 


224 


OUR   BODIES   AND   HOW   WE   LIVE 


We  are  not  so  independent  in  our  daily  actions  as  one 
would  at  first  think.  .  Ten  thousand  unconscious  acts  take 
place  which  tend  to  govern  and  preserve  our  health.  We 
have  as  little  control  over  them  as  we  have  over  the  stars 
above  us. 

301.  Familiar  Examples  of  Reflex  Action.  Let  us  call  to 
mind  a  few  familiar  examples  of  reflex  action.  If  our  feet 

slip  on  the  ice,  with- 
out the  effort  of  the 
will  the  body  tends 
to  recover  itself.  The 
mind  does  not  always 
act,  at  least  in  the 
ordinary  way,  to  pull 
the  fingers  away  when 
they  touch  a  hot  stove. 
We  try  to  brush  the 
flies  away  when  we 
are  asleep. 

By  an  effort  of  the 
will,  we  can  stop  our 
breath  for  a  moment 
or  two ;  but  soon  the 
call  for  air  is  impera- 
tive, and  the  order 
must  be  obeyed,  whether  we  will  or  no.  The  great  work 
of  digestion  is  going  on  day  after  day,  but  we  have  no 
control  over  its  complicated  movements. 

Experiment  67.  To  illustrate  reflex  action.  Tickle  the  inside  of 
the  nose  with  a  feather.  This  does  not  interfere  with  the  muscles  of 
breathing,  but  by  reflex  action  they  come  to  the  help  of  the  irritated 
part,  and  provoke  sneezing  to  clear  and  thus  protect  the  nose. 


FIG.  141.  Dental  Branch  of  One  of  the 
Divisions  of  the  Fifth  Pair  of  Cranial 
Nerves,  supplying  the  Lower  Teeth. 

Branches  from  the  motor  root,  distributed  to 
various  muscles,  are  also  shown. 


THE   NERVOUS   SYSTEM  225 

302.  How  Reflex  Action  gives  Relief  to  the  Brain.    Reflex 
action  relieves  the  "  thinking  centers"  of  the  brain  of  a  vast 
amount  of  work.     If  we  were  forced  to  use  our  will  power 
at  every  step  in  the  process  of  digestion,  the  brain  would 
be  put  to  a  severe  strain.     We  could  not  eat,  and  then 
quietly  go  about  our  business.     If  we  had  to  plan  and  will 
every  heart  beat,  we  should  soon  be  ready  to  give  up  the 
struggle  for  life. 

If  we  had  to  exert  our  will  every  time  we  breathed,  we 
should  soon  get  tired  of  it,  and  long  to  die.  We  could 
never  sleep,  for  the  brain  would  have  to  be  on  the  alert 
to  decide  if  it  were  time  for  the  next  heart  beat,  the  next 
inspiration,  and  the  proper  time  for  each  digestive  fluid 
to  flow. 

303.  The  Spinal  Nerves.     From  the  spinal  cord  thirty- 
one  pairs  of  spinal  nerves  proceed  to  the  trunk  and  the  limbs. 
They  pass  out  on  each  side  of  the  spinal  canal  through 
small  openings  at  the  sides  of  the  backbone. 

Each  of  these  spinal  nerves  has  two  roots,  —  one  going 
from  the  front  part,  and  the  other  from  the  back  part,  of 
the  cord.  These  two  roots  unite  and  form  one  silvery  cord 
as  they  pass  out  from  the  backbone  (Fig.  140). 

The  root  which  goes  from  the  front,  or  anterior,  part  of 
the  spinal  cord  consists  of  motor  fibers  and  controls  muscles. 

The  root  which  comes  from  the  back,  or  posterior,  part  of 
the  cord  consists  of  sensory  fibers  and  transmits  sensations 
from  the  various  parts  of  the  body  to  the  spinal  cord. 

As  each  nerve  trunk  leaves  the  backbone,  it  subdivides 
and  sends  off  branches  into  all  parts  of  the  body.  Each 
branch  contains  fibers  from  both  roots.  If  any  one  of  these 
nerves  or  branches  is  cut  or  injured,  the  power  of  feeling 
and  movement  ceases  in  all  those  parts  to  which  it  is 


226 


OUR   BODIES   AND    HOW  WE   LIVE 


distributed,  — that  is,  those  parts 
The  case  is  not  unlike  that  of 
and  thus  stopping  the  passage 


FIG.  142.  The  Cervical  and  Thoracic 
Portions  of  the  Sympathetic  Nerve  and 
their  Main  Branches. 

In  the  center  of  the  figure,  running  almost 
vertically,  is  shown  the  right  pneumogastric 
nerve.  To  the  left  may  be  seen  a  chain  of 
ganglia  of  the  sympathetic  nerve,  running 
along  the  vertebrae.  The  distribution  of 
some  smaller  ganglia  and  nerve  branches  in 
the  neck  and  chest  regions  are  also  shown. 


of  the  body  are  paralyzed. 

cutting  a  telegraph  wire, 

of  the  electric  current. 

304.  The  Sympathetic 
Nervous  System.  The 
sympathetic  nervous  sys- 

,  tern,1  as  we  have  learned 
(Sec.  289),  consists  of  a 
double  chain  of  nerve 
knots,  or  ganglia,  con- 
nected by  nervous  cords 
running  down  in  front 
and  on  each  side  of  the 
backbone. 

The  knots  of  nerves 
are  connected  with  each 
other,  and  with  the  spinal 
nerves,  by  a  network  of 
nerve  fibers. 

Through  the  sympa- 
thetic ganglia,  nerve 
fibers  from  a  part  of 
each  spinal  nerve  pass 
on  their  way  to  impor- 
tant internal  organs.  A 
close  network  of  the 

1  The  name  "  sympathetic  " 
was  given  to  this  part  of  the 
nervous  system  because  it  was 
believed  that,  through  its 
agency,  distant  organs  have 
sympathy  with  one  another's 
afflictions. 


THE    NERVOUS   SYSTEM 


227 


sympathetic  nerves  is  formed  upon  the  heart,  and  about  the 
lungs,  the  stomach,  and  the  intestines,  as  well  as  around 
the  walls  of  the  minute  arteries  and  capillaries. 

A  large  part  of  the  regulating  action  of  the  vital  organs 
is  controlled  by  the  influences  which  thus  reach  these 
organs  through  the 
sympathetic  nerves. 

305.  How  the  Sym- 
pathetic System  acts. 
It  is  believed  that  the 
sympathetic  nerves  do 
not  serve  as  independ- 
ent nervous  centers. 
The  influences  which 
they  convey  to  the 
great  processes  that 
are  beyond  the  control 
of  the  will,  are  derived 
from  the  brain  or  the 
spinal  cord. 

Therefore  we  may 
think  of  these  great 
networks,  or  plexuses, 
of  nerves,  not  as  a 
separate  nervous 
system,  but  as  an  out- 
lying part  of  the  cerebro-spinal  system.  The  sympathetic  nerves 
are  very  slow  to  act.  A  blush  steals  slowly  up  to  the 
roots  of  the  hair.  If  we  go  from  the  dark  into  a  strong 
light,  we  are  blinded.  The  pupil  of  the  eye  is  too  large. 
An  impression  is  made  on  the  sympathetic  nerve,  which 
causes  it  to  contract  slowly  while  we  are  shading  our  eyes. 


FIG.  143. 

Showing  the  distribution  of  some  of  the  great 
plexuses  of  the  sympathetic  nerve  in  the 
lumbar  and  sacral  regions. 


228  OUR   BODIES  AND   HOW   WE   LIVE 

306.  The  Health  of  the  Nervous  System.    The  health  of 
every  organ  of  the  body  is  dependent  upon  the  welfare 
of  the  nervous  system. 

If  a  tiny  blood  vessel  in  the  brain  is  broken  and  forms 
a  little  clot  as  large  as  a  pea,  a  paralysis  of  one  side  may 
be  produced  by  its  pressure  on  the  delicate  brain  tissue. 
An  overloaded  stomach  may  make  the  brain  dull  and 
stupid  for  some  time.  Indigestion  may  make  one  cross, 
morose,  and  unhappy.  The  long  loss  of  sleep  may  cause 
exquisite  suffering. 

A  slight  blow  on  the  head  may  instantly  rob  a  man  of 
consciousness.  On  the  other  hand,  severe  accidents  to  the 
brain  may  not  produce  serious  results.  By  breathing  in  such 
poisons  as  ether  or  carbonic  acid  gas,  the  blood  is  so  altered 
that  the  brain  ceases  to  act  and  consciousness  vanishes. 

307.  Brain  Power  increased  by  Education.     Like  any 
other  organ,  the  brain  may  be  strengthened  and  increased 
in  its  power  by  education.     Impressions  made  upon  the 
mind  in  early  life  are  more  readily  received  and  more  com- 
pletely retained  than  those  which  are  made  when  the  growth 
of  the  brain  is  far  advanced.     For  this  reason,  education 
should  be  begun  early  in  life ;  and  educational  influences 
brought  to  bear  at  that  time  are  most  effective  in  shaping 
mental  growth.     It  is  an  object  for  which  most  parents  are 
willing  to  work  hard  and  to  exercise  much  self-denial. 

308.  Worry  and  not  Mental  Work  overtaxes  the  Nervous 
System.    Just  as  the  stomach  may  be  overworked  and  fail 
after  a  time  to  digest  food  properly,  and  as  muscles  are 
exhausted  by  overexertion,   so  may  the  nervous  system, 
especially  the  brain,  be  overtaxed. 

Mental  work  is  rarely  hurtful  to  a  healthy  person  who 
takes  good  care  of  himself.  It  is  not  so  much  severe 


THE   NERVOUS    SYSTEM 


229 


mental  toil  as  it  is  worry  that  disturbs  the  mental  poise. 
It  is  not  study,  but  fretting,  that  causes  the  student  to 
break  down  in  his  studies.  Let  young  people  have  plenty 
of  nutritious  food  properly  given,  plenty  of  sound  sleep, 
enough  suitable  clothing,  and  a  calm  and  wise  oversight  at 
home,  and  they  will  rarely  be  injured  by  too  much  study. 

It  is  fretting  about  passing  examinations,  worrying  about 
promotions,  and  other  bane- 
ful influences,  which  have 
become  attached  to  our 
educational  system  like 
barnacles  to  a  stately  ship, 
that  may  make  the  deli- 
cate, sensitive  child  cross, 
peevish,  and  sickly. 

309.  Abuse  of  the  Nerv- 
ous System.  Every  tiny 
cell  of  the  nervous  system 
is  busily  at  work  doing  its 
allotted  duty.  Now,  let  a 
person  fret  and  worry  day 
after  day  over  real  or  fancied 
troubles,  abuse  his  digest- 
ive organs  by  too  much  or  too  little  food,  go  without  proper 
sleep,  smoke  or  chew  tobacco  in  excess,  try  to  prop  up  his 
flagging  energies  with  strong  coffee  or  alcoholic  liquors,  and 
the  strain  on  the  nervous  system  will  make  him,  sooner  or 
later,  a  mental  wreck. 

Like  a  spendthrift  who  spends  his  principal  and  per- 
sists in  calling  it  his  income,  so  is  a  man  who  is  indulging 
in  various  forms  of  dissipation  really  exhausting  the  limited 
amount  of  nervous  force  at  his  command.  Unhealthful  and 


FIG.  144.  Dental  Branches  of  One 
of  the  Divisions  of  the  Fifth  Pair 
of  Cranial  Nerves,  supplying  the 
Upper  Teeth. 


230  OUR   BODIES   AND   HOW  WE   LIVE 

injurious  habits,  whether  in  the  important  or  the  compara- 
tively trifling  matters  of  daily  living,  are  drafts  drawn  on 
the  future,  which  must  be  met  at  no  distant  day  with  all 
the  attendant  perils  of  physical  or  mental  bankruptcy. 

310.  The   Importance  of   Sleep.     The  need  of  sleep  is 
self-evident,  and  the  loss  of  it  is  one  of  the  more  common 
causes  of   ill   health.     The   muscles  and  the  nerves,  the 
brain  in  particular,  are  in  full  activity  when  we  are  awake. 
Repair  goes  on  every  moment,  whether  we  are  awake  or 
asleep.     During  the  waking  hours,  however,  the  waste  of 
the  tissues  is  in  excess  of  the  repair,  while  during  sleep  the 
repair  exceeds  the  waste. 

Hence  the  good  mother,  nature,  at  regular  intervals, 
causes  all  parts  of  the  bodily  machinery  to  be  run  at  their 
lowest  pressure.  In  other  words,  we  are  put  to  sleep. 

311.  Rest  of  Important  Organs  during  Sleep.     During 
sleep  the  heart  beats,  the  lungs  take  in  air,  and  the  stomach 
digests  its  food ;   but  these  great   organic  processes  are 
carried  on  but  feebly.     The  vital  organs  rest  because  they 
are  worked  at  their  lowest  rate. 

The  eye,  the  ear,  the  brain,  and  the  nerves  are  rested  by 
darkness,  silence,  and  unconsciousness.  The  tired  muscles 
thus  regain  their  vigor  and  the  exhausted  brain  is  refreshed. 

Sleep  is  more  or  less  sound  according  to  circumstances. 
Fatigue,  if  not  too  great,  aids  it ;  while  idleness  lessens  it. 
Anxious  thought  and  pain  and  even  anticipated  pleasure 
may  prevent  it.  The  sounder  the  sleep,  the  more  the  body 
and  the  mind  are  refreshed. 

312.  Hints  about  Sleep.  The  best  time  for  sleep  is  at  night. 
The  soundest  and  best  sleep  is  obtained  during  silence  and 
darkness.     People  who  are  forced  to  work  at  night  and  to 
sleep  during  the  day  usually  have  a  strained  and  wearied  look. 


THE    NERVOUS    SYSTEM 


231 


The  amount  of  sleep  necessary  depends  upon  our  occu- 
pation and  our  temperament.  Some  require  little  sleep, 
while  others  need  a  great  deal.  Eight  hours  of  sound  sleep 
for  a  grown  man  or  woman,  and  more  for  children,  is  about 
the  average  amount  required.  Children  naturally  need 
more  sleep  because 
their  bodies  need 
more  rest  during  the 
period  of  growth. 
Hence  the  infant 
sleeps  most  of  the 
time,  if  well  and  prop- 
erly cared  for. 

Little  children 
should  always  be  put 
to  bed  early  and 
allowed  to  sleep  in  the 
morning  until  they 
awake  of  themselves. 
During  hot  weather 
the  active  child  should 
be  undressed,  bathed, 
and  put  to  bed  in  the 
middle  of  the  day  for 
a  good  nap.  Do  not 
go  to  bed  with  the 
brain  excited  or  too  active.  Read  some  pleasant  book,  talk 
quietly,  sing,  take  a  brisk  walk,  or  otherwise  indulge  in  a  little 
quiet  recreation  for  half  an  hour  before  going  to  bed. 

313.  Some  of  the  First  Effects  of  Alcoholic  Liquors  upon 
the  Nervous  System.  The  first  symptom  which  shows  that 
the  nerves  are  disturbed  by  drinking  alcoholic  liquors  is  the 


FIG.  145. 

Showing  some  of  the  superficial  nerves  on  the  left 
side  of  the  neck  and  the  head.  A  few  super- 
ficial muscles  and  arteries  in  the  same  region 
are  also  shown. 


232 


OUR   BODIES   AND   HOW  WE   LIVE 


quickened  action  of  the  heart,  and  with  it  the  dilatation  of 
the  blood  vessels.  The  face  is  flushed  and  there  is  a  glow 
over  the  skin,  because  the  nerves  which  regulate  the  size 
of  the  blood  vessels  are  partially  paralyzed  by  the  alcohol. 
The  tiny  blood  vessels  of  the  brain  are  dilated  and  the 
nerve  cells  are  stimulated.  The  brain 
may  become  more  active,  thoughts 
flow  more  rapidly,  and  the  speech 
become  more  fluent ;  but  such  activ- 
ity is  only  an  indication  of  a  disturb- 
ance of  the  natural  conditions  of  the 
body.  The  power  of  right  thinking 
is  diminished,  and  the  fluent  speech 
in  a  short  time  tends  to  become 
lacking  in  good  sense. 

The  parts  of  the  brain  used  in  the 
higher  processes  of  thought  and  rea- 
soning seem  to  be  the  most  delicate 
and  therefore  most  easily  injured. 
Investigation  has  shown  that  it  is 
these  delicate  parts  of  the  brain 
which  are  first  injured  by  alcohol. 
Thus,  the  common  observation  that 
alcohol  impairs  first  the  higher  func- 
tions of  the  mind  finds  its  confirma- 
tion and  explanation  in  discoveries 
made  by  the  microscope  concerning  the  changes  which  alco- 
hol may  cause  in  the  actual  structures  of  the  brain. 

The  effect  of  wine  sometimes  seen  at  a  social  dinner  where 
those  who  have  taken  moderate  amounts  begin  to  grow  talka- 
tive, excitable,  and  hilarious  represents  an  unnatural  state 
of  the  nervous  system.  Such  persons  are  really  in  the  first 


FIG.  146.  Superficial,  or 
Cutaneous,  Nerves  on 
the  Back  of  the  Left 
Forearm  and  Hand. 


THE   NERVOUS   SYSTEM  233 

stage  of  intoxication,  which  is  that  of  mental  excitement. 
This  brief  period  of  excitement  is  usually  followed  by  the 
depressant  or  narcotic  action  of  alcohol.  It  is  incorrect, 
therefore,  to  call  that  which  produces  progressive  paralysis 
of  the  center  of  the  nervous  system,  both  sensory  and 
motor,  a  stimulant.1 

314.  The  Power  of  Self -Control  weakened  by  Alcohol. 
The  power  of  self-control,  which  is  the  most  difficult  of  the 
human  faculties  to  acquire,  and  the  last  to  be  fully  attained, 
is  the  first  to  be  weakened  by  alcohol.  In  this  fact  lies  the 
danger  of  the  use  of  alcohol  as  a  beverage.  For  example, 
some  men  intend  to  take  only  one  drink  on  some  social  occa- 
sion; but  that  one  drink  so  weakens  their  mastery  of  them- 
selves that  they  drink  glass  after  glass.  Others  set  out  to 
use  alcoholic  drinks  moderately  everyday;  but  usually  as 
time  passes  they  allow  themselves  increasing  limits.  Self- 
control  weakens  under  the  repeated  contact  of  alcohol  with 
the  brain  cells. 

This  is  the  history  of  practically  every  drunkard  ;  while  the 
example  of  those  who  drink  but  do  not  become  drunkards 
leads  astray  thousands  of  others  whose  nervous  systems 

1  Helmholtz,  at  the  celebration  of  his  seventieth  birthday,  spoke  of  ideas 
"  flashing  up  from  the  depth  of  the  unknown  soul "  that  lies  at  the  founda- 
tion of  every  truly  creative  intellectual  production,  and  closed  his  account 
with  these  words :  "  The  smallest  quantity  of  alcoholic  beverages  seems  to 
frighten  them  away." 

Some  people  imagine  that  after  the  use  of  alcohol  they  can  do  things 
more  quickly,  that  they  are  brisker  and  sharper,  but  exact  measurement 
shows  that  they  are  slower  and  less  accurate.  Men  believe  that  they  are 
wiser  and  brighter,  but  their  sayings  are  more  automatic  and  apt  to  be 
profane.  To  quote  T.  Leander  Brunton,  M.D.,  of  London,  England,  "  It 
produces  progressive  paralysis  of  the  judgment,"  and  this  begins  with  the 
first  glass.  Men  say  and  do,  even  after  drinking  a  single  glass  of  liquor, 
what  they  would  not  say  or  do  without  it,  and  therefore  it  clearly  affects 
the  brain  and  diminishes  self-control.  —  G.  SIMS  WOODHEAD,  M.D. 

N 


234  OUR   BODIES  AND   HOW   WE   LIVE 

are  more  quickly  injured  by  alcohol  or  whose  conditions 
in  life  are  less  favorable  for  resisting  its  effects.1 

315.  The  Next  Step.     Smaller  quantities  of  alcohol  than 
those  usually  considered  moderate  can  be  shown,  by  fine 
tests,  to  weaken  self-control.     If  more  is  taken,  there  grad- 
ually follows  loss  of  power  over  some  of  the  muscles,  and 
the  energy  of  the  whole  muscular  system  is  lessened.     The 
muscles  of  the  lower  lip  and  the  legs  are  the  first  to  feel 
this  unnatural  torpor.     The  speech  is  thick  and  the  gait 
uncertain. 

The  nerve  cells  of  the  higher,  or  controlling,  part  of  the 
brain  may  soon  be  brought  within  the  grasp  of  the  alcoholic 
influence,  and  the  faculties  of  the  mind  are  still  more 
impaired.  Reason  is  off  duty,  and  the  lower,  or  animal, 
impulses  begin  to  manifest  themselves.  First,  the  control 
of  judgment  and  the  will  disappears,  and  the  emotional, 
the  impulsive,  and  the  purely  instinctive  part  of  our  nature 
is  laid  bare.2 

316.  The  Last  Stage.     In  the  last  stage  which  may  result 
even  from  drinking  a  single  large  amount  of  alcohol,  the 
paralysis  of  the  nerve  centers  and  of  the  brain  is  carried  to 
a  greater  extent.     All  the  inlets  of  the  senses  are  closed, 

1  Men  following  intellectual  pursuits  are  apt  to  be  victims  of  mental 
and  bodily  degradation  through   alcohol,  for  once  they  come  under  its 
subtle  control,  the  craving  for  it  in  men  of  educated  brains  is  perhaps 
stronger  than  in  men  of  uneducated  brains.  —  T.  S.  CLOUSTON,  M.D. 

Alcohol  destroys  the  individuality  of  man  and  paralyzes  his  body  and 
his  will  power.  — A.  BAER,  M.D. 

2  The  stimulating  action  which  alcohol  appears  to  exert  on  the  func- 
tions of  the  brain  is  only  a  paralytic  action.     The  cerebral  functions  which 
are  first  interfered  with  are  the  power  of  clear  judgment  and  reason.     The 
lively  gesticulations  and  useless  exertions  of  intoxicated  people  are  due  to 
a  kind  of  paralysis,  —  the  restraining  influences  being  removed  which  pre- 
vent a  sober  man  from  uselessly  expending  his  strength.  —  G.  VON  BUNGE, 
Professor  of  Physiological  Chemistry,  University  of  Basel. 


THE   NERVOUS   SYSTEM  235 

all  consciousness  and  sensation  are  lost,  and  all  power  over 
the  voluntary  movements  is  gone.  The  heart  still  beats, 
the  blood  circulates,  and  the  breathing  still  goes  on;  but 
these  are  the  sole  remnants  of  vitality,  —  the  slender 
threads  by  which  a  hold  is  retained  upon  life. 

317.  Progressive  Changes  in  Character  caused  by  Strong 
Drink.  The  person  who  habitually,  or  even  occasionally, 
stupefies  his  faculties  or  paralyzes  his  judgment  and  reason 
with  alcoholic  drinks  disqualifies  himself  by  this  action  for 
responsible  duties.  In  family  and  social  relations  he  is 
often  irritable,  unjust  in  his  judgments,  careless 'sometimes 


FIG.  147.     The  Main  Nerve  Trunks  of  the  Right  Forearm,  showing  the 
Accompanying  Radial  and  Ulnar  Arteries.     (Anterior  view.) 

to  the  extent  of  absolute  cruelty  in  his  responsibilities  to 
those  related  to  him  by  the  tenderest  ties.  In  business  he 
becomes  incapable  of  continued  application,  loses  the  sense 
of  responsibility,  and  may  become  actually  dishonest. 

Most  railroads  now  demand  total  abstinence  of  their 
employees.  From  a  strictly  business  point  of  view  it  does 
not  pay  great  corporations  to  employ  engineers,  switchmen, 
telegraph  operators,  or  men  in  any  responsible  position  who 
use  alcoholic  liquors.  The  directors  know  too  well  that  the 
risk  of  life,  limb,  and  property  is  thereby  greatly  increased. 

Other  industries  are  rapidly  adopting  the  same  meas- 
ures as  a  protection  against  loss  and  accidents.  Insurance 


236  OUR  BODIES  AND   HOW  WE   LIVE 

companies  class  even  moderate  but  habitual  users  of  alcoholic 
liquors  as  "extra  risks."  The  great  mass  of  statistics 
gathered  by  these  companies,  bearing  upon  the  tenure  of 
human  life,  go  to  show  that  the  man  who  never  drinks 
alcoholic  beverages  is  likely  to  live  longer  than  one 
who  does. 

318.  The  Final  Result  of  Alcoholism.     After  a  longer 
or  a  shorter  time  the  usual  result  of  the  continuous  use 
of  alcoholic  liquor  is  steadily  to  weaken  the  self-control  of 
its  victim,  and  at  last  to  make  him  a  slave  to  his  lower 
nature.     The  craving  for  ardent  spirit  becomes  well-nigh 
irresistible.     Self-respect,  honor,  conscience,  everything,  is 
sacrificed  in  this  craving  for  strong  drink. 

The  disease  known  as  delirium  tremens,  meaning  a 
trembling  madness,  is  not  an  uncommon  instance  of  the 
profound  effect  of  the  habitual  use  of  alcohol  upon  the 
nerve  centers. 

There  is  still  another  depth  of  ruin  in  such  a  downward 
course,  and  that  is  insanity.  In  fact,  every  instance  of  com- 
plete intoxication  is  a  case  of  temporary  insanity,  —  that 
is,  of  mental  unsoundness  with  loss  of  self-control.  Per- 
manent insanity  may  be  one  of  the  last  results  of  intem- 
perance. Alcoholism  sends  to  our  insane  asylums  a  large 
proportion  of  their  inmates,  as  ample  records  testify.1 

319.  Moral  Effect  of  the  Alcoholic  Habit.     The  once 
active  will  power  of  the  man  who  has  become  the  victim 
of  alcohol  is  a  thing  of  the  past.     He  can  no  longer  resist 
the  feeblest  impulse  to  temptation.     The  grand  faculty  of 

1  About  thirty  per  cent  of  the  male  cases  in  lunatic  asylums  where 
inebriates  are  taken  may  be  classed  as  direct  alcoholic  lunacy.  The 
indirect  victims  of  the  drunken  habits  of  their  ancestors  no  doubt  form 
a  larger,  but  incalculable,  number  of  the  inmates  of  such  asylums. — 
A.  FOREL,  M.D. 


THE   NERVOUS   SYSTEM 


237 


self-control  is  lost,  and  as  a  result  the  baser  instincts  of 
his  lower  nature  are  now  uppermost ;  greed  and  appetite 
often  rule  unrestrained. 

The  moral  power  of  such  a  man  is  also  dragged  down 
to  the  lowest  depths.  The  finer  sensibilities  of  character 
are  deadened;  pride  of  personal 
appearance,  nice  self-respect  and 
proper  regard  for  the  good  opinion 
of  others,  the  sense  of  decorum, 
are  gone,  and  at  last  even  decency 
disappears.  Dignity  of  behavior 
may  yield  to  silliness,  and  the 
person  lately  respected  becomes 
an  object  of  pity  and  loathing. 

Convictions  of  right  and  wrong 
now  find  little  place  in  his  nature ; 
conscience  is  silenced,  dishonesty 
prevails.  This  is  true  both  as  to 
solemn  promises,  and  also  as  to 
property.  The  drunkard  may 
resort  to  any  form  of  fraud  or  theft 
to  feed  the  consuming  craving  for 
more  alcohol. 

320.  Hereditary  Results  of 
Strong  Drink.     We   may  inherit 
mental  and  physical  vigor  or  weak- 
ness, our  features,  and  even  moral 
tendencies.     The  children  of  par- 
ents whose  brains  are  injured  by  alcohol  are  more  prone 
than  others  to  mental  disorders  and  to  those  widely  varied 
diseases  which,  for  lack  of  a  better  name,  we  vaguely  call 
"  nervous."     This  is  proved  by  the  unusual  prevalence  in 


FIG.  148.  A  Great  Nerve 
(Crural)  and  its  Branches 
on  the  Front  of  the  Thigh. 

The  femoral  artery  with  its  cut 
end  is  shown. 


238  OUR  BODIES   AND   HOW   WE   LIVE 

such  families  of  infant  mortality,  convulsions,  epilepsy, 
hysteria,  obscure  brain  diseases,  and  imbecility.1 

321.  Tobacco  and  its  Effect  upon  the  Nerve  Centers. 
Tobacco,  whether  snuffed,  chewed,  or  smoked,  is  a  nar- 
cotic and  a  poison.  Its  injurious  effects  are  due  to  its 
active  principle  called  nicotine,  which  is  a  narcotic  poison.2 

Tobacco  is  hurtful  to  young  people,  and  by  no  means 
free  of  harm  to  adults.  It  produces  an  artificial  exhaustion, 
as  it  were,  of  the  nerve  centers.  The  tobacco  habit  once 
acquired  generally  leads  to  continual  and  increasing  use. 

Thus,  after  a  time,  tobacco  may  produce  functional 
derangement  of  the  nervous  system,  palpitation  of  the 
heart,  certain  forms  of  dyspepsia,  and  more  or  less  irrita- 
tion of  the  throat  and  lungs.3 

Sometimes,  after  long  smoking,  a  sensation  of  dizziness, 
with  a  momentary  loss  of  consciousness,  is  experienced. 
While  the  stomach  is  empty,  protracted  smoking  will  often 
produce  a  feeling  of  nausea,  accompanied  by  a  headache. 

1  Of  all  the  effects  of  alcohol,  none  are  so  deplorable  as  the  fact  that 
the  offspring  must  suffer  for  the  craving  of  its  parents.     This  is  more 
apparent  when  both  father  and  mother  have  been  habitual  alcoholics. — 
P.  M.  LIGHTFOOT,  M.D. 

A  man  may  claim  that  he  has  drunk  whisky  all  his  life  and  is  yet  in  a 
good  state  of  preservation.  Such  may  be  the  case,  but  to  see  the  full 
effect  of  his  habit,  look  at  his  children,  and  we  find  that  they  will  not  com- 
pare favorably  with  those  whose  parents  have  not  been  given  to  strong 
drink. — Journal  of  the  American  Medical  Association. 

2  The  external  application  of  tobacco  to  chafed  surfaces,  and  even  to 
the  healthy  skin,  will  occasion  severe  and  sometimes  fatal  results.  .  A  tea 
made  of  tobacco,  and  applied  to  the  skin,  has  caused  death  in  three  hours. 
Smoking  a  large  quantity  of  tobacco  at  one  time  has  been  known  to  pro- 
duce violent  and  even  fatal  effects.     Nicotine  is  one  of  the  most  rapidly 
fatal  poisons  known.     It  takes  about  one  minute  for  a  single  drop  to  kill 
a  full-grown  cat.     One  drop  has  killed  a  rabbit  in  three  minutes. 

3  I  never  smoke  because  I  have  seen  the  most  efficient  proofs  of  the 
injurious  effects  of  tobacco  on  the  nervous  system.  —  CHARLES  IIDOUARD 
BROWN-SEQUARD,  M.D. 


THE   NERVOUS   SYSTEM 


239 


322.  Effect  of  Tobacco  upon  the  Nervous  System.     The 
cells  of  the  brain  may  become  poisoned  from  tobacco.    The 
ideas  may  lack  clearness  of  outline.     The  will  power  may 
be  weakened,  and  it  may  be  an  effort  to  do  the  routine 
duties    of    life.      The   old    tobacco 

user  is  often  cross,  irritable,  and 
liable  to  outbursts  of  passion.  The 
memory  may  also  be  impaired. 

The  narcotic  principle,  the  deadly 
nicotine,  has  retarded  the  nutrition 
of  the  delicate  nerve  cells.  The 
nerve  centers  are  no  longer  able  to 
hoard  up  their  usual  amount  of  vital 
energy.  Hence  arise  the  many  and 
various  nervous  symptoms  due  to  the 
poisonous  effect  of  tobacco.  Many 
men  in  mature  life,  especially  those 
engaged  in  sedentary  occupations, 
suffer  from  nervous  breakdown  in 
consequence  of  the  habitual  use  of 
this  noxious  weed. 

323.  Smoking    Cigarettes.      The 
smoking  of  cigarettes  cannot  be  too   FlG 
severely  condemned.    They  are  often 
made  of  the  cheapest  materials,  and 
sometimes  " doctored"  with  refuse 
substances,  and  even  forms  of  opium, 

in  order  to  give  some  bulk  and  "tone"  to  the  originally 
cheap  material.  Cigarettes  are  so  common  and  so  cheap 
that  their  use  by  thousands  of  young  persons  has  become  a 
serious  matter.  The  laws  of  many  states  very  properly  for- 
bid the  sale  of  tobacco,  especially  of  cigarettes,  to  minors. 


A  Great  Nerve 
(Posterior  Tibial)  on  the 
Back  of  the  Leg,  with  its 
Accompanying  Artery  of 
the  Same  Name. 


240  OUR   BODIES   AND   HOW  WE   LIVE 

324.  Effects  of  Tobacco  upon  Young  People.     Tobacco, 
in  any  form,  has  a  peculiarly  injurious  effect  upon  young 
and  growing  persons.1     It  not  only  stunts  their  growth, 
but  produces  a  weakened  state  of  the  system,  which  tends 
greatly  to  impair  muscular  and  mental  activity.     The  pro- 
found effect  that  tobacco  has  upon  the  nervous  system 
after  the  first  trial  of  smoking  or  chewing  is  matter  of 
familiar  experience. 

Even  after  the  system  gets  used  to  the  narcotic,  young 
people  continue  to  surfer  oftentimes  from  nausea,  dizziness, 
headache,  muscular  trembling,  loss  of  appetite,  and  general 
weakness. 

Here  is  one  bit  of  advice  for  you  to  remember  all  the 
days  of  your  life :  Do  not  smoke  or  chew  tobacco  if  you 
wish  to  keep  strong  and  well,  and  to  succeed  in  life. 

325.  The  Use  of  Tobacco  from  a  Moral  Point  of  View. 
The  effect  of  tobacco  on  the  moral  nature  often  shows 
itself  in  a  selfish  disregard  for  the  rights  of  others.     The 
smoker  has  no  right  to  make  with  his  tobacco  smoke  the 
air  about  him  unfit   for  others  to  breathe.     He  has  no 
right  to  puff  his  smoke  into  the  faces  of  people  on  the 
streets,  or  thus  to  pollute  the  air  of  public  places  which 
others  are  obliged  to  share  with  him. 

The  fact  that  he  does  this  knowing  that  to  many  people 
the  smoke  of  tobacco  is  offensive,  and  that  some  are  even 

1  While  tobacco  is  injurious  to  every  one,  it  is  far  more  harmful  to  those 
who  are  growing.  A  boy  who  uses  tobacco  can  never  have  the  strength 
of  body  or  the  vigor  of  mind  he  would  have  had  except  for  its  use.  Boys 
and  young  men  entering  the  employ  of  a  great  business  house  or  a  corpo- 
ration where  their  success  depends  upon  strength,  alertness,  skill,  and 
accuracy,  as  well  as  integrity  and  industry,  would  surely  reach  a  much 
higher  success  if  they  abstained  totally  from  all  narcotics.  —  WINFIELD  S. 
HALL,  M.D.,  Northwestern  University  Medical  School,  Chicago. 


THE   NERVOUS    SYSTEM 


24I 


made  sick  by  it,  shows  his  lack  of  refinement  as  well  as 
moral  sense.  Other  evidence  of  the  same  character  is 
the  filthy  habit  of  spitting  on  sidewalks,  floors,  stoves,  and 
other  objects,  with  "which  some  smokers  and  chewers  of 
tobacco  disgust  all  cleanly  people. 

326.  Harmful  Effect  of  Tobacco 
upon  the  Mental  Development  of 
Young  Students.  Our  military  and 
naval  academies  and  many  semi- 
naries and  colleges  very  properly 
prohibit  the  use  of  tobacco  by  their 
students.  The  honors  of  the  great 
schools,  academies,  and  colleges  are 
very  largely  taken  by  the  abstainers 
from  tobacco.  This  is  proved  by 
the  result  of  repeated  and  exten- 
sive comparisons  of  the  advanced 
classes  in  a  great  number  of  sec- 
ondary schools  and  colleges  both 
in  this  country  and  in  Europe. 

The  reason  for  this  is  plain.  The 
mind  of  the  habitual  user  of  tobacco 
is  apt  to  lose  its  capacity  for  study 
or  successful  effort.  This  is  espe- 
cially true  of  boys  and  young  men. 
The  growth  and  development  of  the 
brain  having  been  once  retarded, 
the  youthful  user  of  tobacco  has 
established  a  permanent  drawback  which  may  hamper  him 
all  his  life.  The  keenness  of  his  mental  perception  may  be 
dulled  and  his  ability  to  seize  and  hold  an  abstract  thought 
may  be  impaired. 


FIG.  150.  A  Great  Nerve 
(Plantar)  and  its  Branches 
which  supply  th'e  Bottom 
of  the  Feet. 

Note  the  cut  tendons  of  the 
great  muscles  of  the  leg. 


242  OUR  BODIES   AND   HOW  WE   LIVE 

327.  Opium  and  its  Various  Forms.     Opium,  one  of  the 
most  powerful  of  the  narcotic  poisons,  is  the  dried  juice 
of  the  white  poppy.     It  has  the  power  of  deadening  the 
nerves  and  producing  a  kind  of  deep  sleep  or  stupor. 

Morphine,  a  white  powder,  is  a  very  condensed  form  of 
opium.  Laudanum  is  an  alcoholic  solution  of  opium.  Pare- 
goric is  a  diluted  and  flavored  form  of  an  alcoholic  tincture 
of  opium. 

The  various  forms  of  opium  are  very  generally  used  in 
patent  medicines.  They  form  the  "  soothing  "  basis  of  lini- 
ments, cough  killers,  soothing  sirups,  stomach  bitters, 
cholera  mixtures,  and  numerous  other  preparations  which 
some  persons  are  eager  to  buy,  hoping  to  get  relief  from 
some  real  or  fancied  disease. 

328.  The  Ruin  wrought  by  Opium  upon  its  Victim.     The 
habit  of  taking  opium  completely  changes  its  victim.     A 
once  upright  and  honest  man  will  lie,  cheat,  and  defraud, 
to  satisfy  his  craving  for  this  baneful  drug.     Promises  and 
resolutions  to  stop  its  use  may  be  honestly  made,  but  are 
no  more  binding  than  ropes  of  sand. 

329.  What  may  lead  to  the  Opium  Habit.     Some  persons, 
jaded  with  business  or  with  worry,  and  unable  to  sleep, 
unwisely  resort  to  some  narcotic  mixture  to  procure  rest. 
Occasionally  persons  getting  better  from  some  serious  sick- 
ness in  which  opiates  were  taken  find  that  the  desire  for 
these- drugs  clings  to  them  long  after  recovery.     In  these 
and  other  similar  cases,  the  use  of  opiates  is  always  most 
dangerous. 

330.  The  Opium  .Habit.     Opium   is  a  most    dangerous 
drug  because  its  use  is  so  liable  to  lead  to  the  opium  habit 
This  is  a  craving  for  opium  that  makes  life  a  burden  for  its 
victim.     The  person  may  have  begun  its  use  in  the  most 


THE   NERVOUS   SYSTEM  243 

innocent  way  to  relieve  pain  or  to  secure  rest.  But  before 
he  realizes  his  peril,  he  finds  that  it  is  all  but  impossible  to 
leave  off  its  use. 

331.  Caution  in  the  Household  Use  of  Opium.    Never  rub 
any  form  of  opium  upon  an  abraded  surface  to  relieve  pain . 
It  may  be  rapidly  taken  up  by  the  blood.     Rubbing  the 
gums  of  teething  children  with  paregoric,  putting  laudanum 
into  a  child's  aching  tooth  or  ear,  giving  either  preparation 
for  "summer  complaints,"  and  many  other  ways  of  using 
opium,  are  dangerous  practices.      Laudanum  that  has  been 
kept   in   the    house   for  a  long   time  may  become  much 
stronger  than  at  first,  on  account  of  the  evaporation  of 
the  alcohol. 

The  so-called  soothing  sirups  and  cough  or  cholera  mix- 
tures often  given  to  infants  and  young  children  all  contain 
more  or  less  of  some  form  of  opium.  The  child  is  simply 
drugged,  and  not  cured,  however  "soothing"  the  effect 
may  be.  The  only  safe  rule  is,  never  to  put  opium  on  the 
list  of  home  remedies. 

332.  Chloral.     Chloral   is  a  powerful  drug,  capable,  in 
small  doses,  of  producing  sleep.     This  action  is  probably 
due  to  its  direct  effect  upon  the  brain.     In  full  doses  it 
depresses  the  action  of  the  nerve  centers  of  the  brain  and 
spinal  cord. 

Because  chloral  is  known  to  induce  sleep,  especially  in 
those  who  suffer  from  excessive  mental  strain,  or  from 
anxiety,  or  other  like  cause,  it  has  come,  of  late  years,  to 
be  used  often  without  a  physician's  advice. 

333.  The  Chloral  Habit.    Like  all  narcotics,  the  chloral 
dose  must  be  steadily  increased  to  get  the  required  effect. 
The  chloral  habit  is  soon  formed,  and  the  person  becomes  a 
slave  to  a  dangerous  drug.     Without  it,  the  chloral  eater 


244  OUR  BODIES  AND   HOW  WE   LIVE 

cannot  sleep ;  with  it,  his  digestion  is  sadly  out  of  order. 
He  suffers  from  dyspepsia,  shortness  of  breath,  and  palpi- 
tation of  the  heart.  The  only  safe  rule  is,  never  to  touch 
so  powerful,  uncertain,  and  dangerous  a  drug. 

334.  Other  Powerful  Drugs  and  Narcotics.     Chloroform, 
ether,  cocaine,  and  other  narcotics  should  never  be  used, 
even  in  the  smallest  doses,  except  under  medical  advice. 
They  are  dangerous  agents  at  all  times,  and  are  used  with 
great  caution,  even  by  physicians.     Persons  who  get  into 
the  habit  of  tampering  with  such  powerful  drugs  run  the 
ever-present  risk  of  killing  themselves  by  an  overdose. 

335.  Some    Other    Dangerous    Drugs.     Since    the   far- 
reaching    epidemic    known  as    influenza,   or   la   grippe,   or 
"grip,"  has  made  such  sad  havoc  in  recent  years  with  the 
lives  and  health  of  the  people,  a  new  class  of  powerful 
drugs  has   come  into  popular  use.     These   remedies  are 
too  dangerous  and  uncertain  for  household  use. 

The  drugs  sold  as  "  headache  "  remedies  should  be  let 
severely  alone.  If  a  person  has  a  headache,  it  is  better  to 
find  the  cause,  so  that  it  may  be  avoided  in  future,  than  to 
continue  the  wrong  living  that  brings  on  the  headache  and 
then  try  to  relieve  it  by  the  use  of  harmful  drugs. 

Kola  and  coca  are  drugs  now  widely  advertised  as  harm- 
less and  as  nerve  restorers.  This  is  not  true.  Any  feeling 
of  restoration  which  these  drugs  may  at  first  produce  is  a 
delusion  that  must  be  paid  for  afterward  by  feelings  of  lassi- 
tude and  weakness.  Nature  alone  holds  the  magic  cordials 
which  really  have  power  to  restore  lost  strength  or  vigor. 
Her  prescriptions  are  rest,  food,  pure  air,  sunlight,  and  a 
cheerful  mind. 


THE   NERVOUS   SYSTEM  245 


QUESTIONS  ON  THE  TEXT 

I.  What  have  we  learned  in  preceding  chapters  to  show  that  all 
parts  of  the  body  work  together  in  harmony?     2.   How  may  the 
nervous  system  be  compared  to  a  telegraph  system?     3.  Of  what 
is   nerve   tissue  made  up?     4.  Describe   nerve   cells.     5.  Describe 
the  structure  of  nerve  fibers.     6.  What  simple  experiment  illustrates 
the  structure  of  a  nerve?     7.  What  is  the  general  arrangement  of  the 
nervous  system?     8.  Of  what  does  the  brain  consist?     9.  What  are 
the  most  important  functions  of  the  brain?     10.  What  can  you  say 
about  the  weight  of  the  brain? 

II.  What  are  the  three  principal  parts  of  the  brain?     12.  Describe 
the  cerebrum.    13.  Describe  the  cerebellum.    14.  What  is  the  medulla 
oblongata?    15.  What  are  cranial  nerves?    16.  Describe  the  spinal 
cord.     17.  What  is  reflex  action?     18.  Give  some  familiar  illustra- 
tions of  reflex  action.     19.  How  does  reflex  action  give  relief  to  the 
brain  ?     20.  Describe  the  spinal  nerves. 

21.  What  is  the  sympathetic  nervous  system?  22.  State  briefly 
how  the  sympathetic  system  acts.  23.  By  what  apparently  slight 
causes  may  the  health  of  the  nervous  system  be  disturbed?  24.  How 
may  the  brain  power  be  increased  ?  25.  What  is  the  effect  of  worry 
on  the  nervous  system  ?  26.  What  can  be  said  about  the  importance 
of  sleep?  27.  Give  some  practical  points  about  sleep.  28.  What 
are  some  of  the  first  effects  of  alcoholic  liquors  upon  the  nervous 
system?  29.  Show  how  the  power  of  self-control  is  weakened  by 
strong  drink.  30.  What  are  some  of  the  progressive  changes  in 
character  caused  by  alcoholic  liquors  ? 

31.  What  are  some  of  the  final  results  of  alcoholism?  32.  What 
is  the  moral  effect  of  the  alcohol  habit?  33.  What  may  be  the 
hereditary  results  of  strong  drink  ?  34.  State  in  a  general  way  the 
effect  of  tobacco  upon  the  nervous  system.  35.  What  is  the  effect  of 
tobacco  upon  the  physical  health  of  young  people  ?  36.  How  may 
tobacco  retard  the  mental  development  of  young  students  ?  37.  What 
is  opium,  and  what  are  some  of  its  various  forms?  38.  What  is 
meant  by  the  opium  habit?  39.  What  is  chloral  and  what  is  the 
chloral  habit?  40.  Mention  some  other  dangerous  drugs  and  give 
some  precautions  about  their  use. 


CHAPTER  XI 
THE  SPECIAL  SENSES 

336.  Sensation.     Everybody  knows  that  the  tongue  is 
sensitive  to  taste,  the  nose  to  smell,  the  ear  to  sound,  and 
the  eye  to  light.     In  other  words,  each  one  of  our  sense 
organs  has  its  own  peculiar  structure  and  is  sensitive  to 
some  special  agency  called  a  stimulus.     These  stimuli  give 
rise  to  nerve  impulses  or  sensations  which  are  transmitted 
by  nerve  fibers  to  the  central  nervous  system. 

Exactly  how  feeling,  or  sensation,  leaves  its  imprint  on  the 
cells  of  the  brain  and  rises  to  consciousness  is  not  known. 

337.  General  Sensations.     Some  sensations,  or  feelings, 
are  of  a  very  general  character.     Thus,  we  have  a  feeling  of 
hunger  or  thirst,  indicating  a  need  of  food  or  drink.     To 
these  may  be  added  the  sensations  of  pain,  tickling,  and 
itching.     Other  general  sensations,  such  as  those  of  fatigue, 
restlessness,  and  faintness,  spring  up  within  us  in  some 
mysterious  way,  sometimes  without  any  obvious  cause. 

338.  Sensations  resulting  from  an  Outward  Agency.   The 
great  majority  of  sensations,  however,  result  from  some  out- 
ward stimulus  or  agency.     Thus,  if  we  hear  a  child  cry  or  a 
bird  sing,  we  have  a  sensation  of  sound.     If  we  put  a  piece 
of  sugar  on  the  tongue,  hold  a  rose  to  the  nostrils,  or  prick 
the  skin  with  a  needle,  certain  sense  organs  receive  the 
impressions.     The  sensory  nerves  carry  these  impressions 
to  the  brain,  and  we  become  conscious  of  a  sensation. 

246 


THE    SPECIAL  SENSES 


247 


339.  The  Special  Senses.     There  are  certain  avenues  by 
which  we  get  information  concerning  the  world  around  us. 
In  other  words,  we  are  provided  with  a  number  of  special 
senses  by  means  of  which  information  is  furnished  us  regard- 
ing outward  forces  and  objects. 

These  special  sense  organs,  or  "gateways  of  knowledge," 
are  the  skin,  the  chief  organ  of  touch  and  temperature ;  the 
tongue,  the  chief  organ  of  taste  ;  the  nose,  of  smell ;  the  ear, 
of  hearing  ;  and  the  eye,  of  sight. 

340.  Touch.    The  sense  of  touch  is  the 
most  widely  extended  of  all  the  senses, 
and  perhaps  the  simplest.      It  has   its 
seat  in  the  skin  all  over  the  body  and  in 
the  lining  of  the  mouth  and  nasal  pas- 
sages.    By  this  sense  of  touch  we  can 
tell  whether  a  body  is  hard  or  soft,  hot 
or  cold,  rough  or  smooth. 

We  have  learned  about  the  thousands 
of  tiny  hillocks  called  papillae,  which  form 
rows  of  very  thick  ridges  on  the  tips  of 
the  fingers  (Sec.  254). 

Now,  besides  a  tiny  artery  and  vein,  finer  than  the  finest 
hair,  there  is  in  each  papilla  the  end  of  a  sensory  nerve. 
Where  the  sense  of  touch  is  most  delicate,  the  papilla  is 
found  to  contain  a  little  oval  bulb  called  the  touch  corpuscle. 

NOTE.  —  There  is  another  sense,  commonly  known  as  the  muscular 
sense,  which  enables  us  to  judge  the  weight  of  different  bodies  accord- 
ing to  the  muscular  effort  required  to  lift  or  hold  them.  This  sense 
becomes  so  highly  developed  by  use  that  shopkeepers  and  others  who 
sell  various  articles  by  weight  can  often  tell  the  weight  of  a  body  by 
simply  balancing  it  in  their  hands. 

The  sense  of  heat  and  cold,  or  sensation  of  temperature,  may  also 
be  regarded  as  a  distinct  sense. 


FIG.  151.    A  Papilla 

of  the  Skin,  with  a 
Touch  Corpuscle. 
Highly  magnified. 


248  OUR  BODIES   AND   HOW  WE   LIVE 

All  parts  of  the  body  have  not  this  sense  of  touch  in  an 
equal  degree.  The  sense  of  touch -is  most  delicate  in  the 
tip  of  the  tongue,  the  tips  of  the  fingers,  and  the  edges  of 
the  lips,  and  least  delicate  in  the  middle  of  the  back.1 

341.  Sensations  of  Heat  and  Cold.  The  skin  also  judges 
to  a  certain  extent  of  heat  and  cold.  These  sensations  can 
be  felt  only  by  the  skin  and  the  lining  membrane  at  the 
entrance  to  various  passages. 

The  sensitiveness  of  the  skin  to  heat  and  cold  varies  in 
different  parts  of  the  body.  The  palms  of  the  hands  and 
the  bends  of  the  joints  are  sensitive  parts.  A  woman  holds 
her  iron  near  her  cheek  to  tell  whether  or  not  it  is  hot. 
Nurses  test  the  heat  of  the  baby's  bath  by  plunging  the 
elbow  into  the  water. 

Experiment  68.  To  illustrate  the  muscular  sense.  Take  two 
equal  iron  or  lead  weights  ;  heat  one  and  leave  the  other  cold.  The 
cold  weight  will  feel  the  heavier. 

Experiment  69.  To  test  the  sense  of  locality.  Ask  a  person  to 
shut  his  eyes ;  touch  some  part  of  his  body  lightly  with  the  point  of 
a  pin,  then  remove  it,  and  ask  him  to  indicate  the  spot  touched. 

Experiment  70.  Our  sensations  of  heat  and  cold  depend  on  the 
temperature  of  the  skin.  Place  one  hand  in  cold  and  the  other  in  hot 
water,  then  plunge  both  in  lukewarm  water.  To  the  cold  hand  the  luke- 
warm water  will  appear  hot,  while  to  the  warm  hand  it  will  seem  cold. 

1  The  sense  of  touch  may  be  said  to  belong  to  every  animated  being, 
and  is  one  great  characteristic  of  animal  life.  In  many  animals  the  tongue 
is  an  instrument  of  touch  as  well  as  of  taste.  Certain  animals,  in  addition 
to  the  tongue,  have  special  organs  of  touch,  such  as  the  whiskers  of  the  cat 
and  the  rabbit.  These  are  really  parts  of  the  skin. 

There  is  no  other  sense  so  capable  of  improvement  as  that  of  touch. 
The  blind  learn  to  read  with  ease  by  passing  their  fingers  over  raised  letters. 
A  famous  botanist  was  blind,  but  was  able  to  distinguish  rare  plants  by  the 
fingers  and  by  the  tip  of  the  tongue.  The  silk  weavers  of  Bengal  are  said 
to  be  able  to  distinguish,  by  the  touch  alone,  twenty  different  degrees  of 
fineness  in  the  unwound  cocoons. 


THE   SPECIAL  SENSES 


249 


342.  Taste.  The  sense  of  taste  is  located  chiefly  in  the 
tongue.  Its  surface  is  covered  with  countless  numbers  of 
tiny  hillocks,  or  papillae,  which  are  abundantly  supplied  with 
delicate  nerve  fibers  from  two  great  nerve  branches  leading 
from  the  brain.1 
These  are  the 
nerves  of  taste.  In 
many  of  the  papil- 
lae are  peculiar 
structures  called 
taste  buds,  or  taste 
goblets,  which  are 
believed  to  be  con- 
nected with  nerve 
fibers.  Similar 
taste  buds  are  scat- 
tered over  the  sur- 
faces of  the  soft 
palate  and  the  epi- 
glottis. 

It  makes  a  dif- 
ference in  the  taste 
whether  we  put  a 
substance  to  be 
tasted  on  the  tip 


FIG.  152.     The  Tongue. 

,  epiglottis  ;  JB,  glands  at  the  base  of  tongue  ;  C,  ton- 
The various  kinds  of  papillae  are  plainly  shown. 


sil. 


Or  the  back  Of  the 

Thus,  sugar  or  any  other  sweet  substance  is  tasted  best 
at  the  tip,  while  a  bitter  substance,  like  quinine,  tastes 
more  bitter  at  the  back  of  the  tongue. 

1  In  certain  animals  the  papillae  are  very  largely  developed  and  give  a 
roughness  to  the  tongue.  It  is  this  which  enables  the  lion  or  the  tiger  to 
strip  off  the  flesh  from  a  bone  by  simply  licking  it. 


250 


OUR  BODIES   AND    HOW  WE   LIVE 


The  sensations  of  the  tongue  are  very  complex.  They 
are  really  combinations  of  the  sensations  of  touch  and 
taste.  Strictly  speaking,  we  can  tell  by  the  sense  of  taste 
only  whether  anything  is  bitter,  sweet,  sour,  or  salt.  We 
detect  the  flavor  of  food  and  drink  by  the  sense  of  smell. 

Experiment  71.  Wipe  the  tongue  dry  and  lay  on  its  tip  a  few 
grains  of  granulated  sugar.  It  is  not  tasted  until  it  is  dissolved. 
Apply  a  few  grains  of  sugar  to  the  tip,  and  a  few  more  to  the  back, 
of  the  tongue.  The  sweet  taste  is  more  pronounced  at  the  tip. 

Experiment  72.  Prepare  a  solution  of  sulphate  of  quinine  by  dis- 
solving a  small  quinine  pill  in  a  tablespoonful  of  hot  water.  It  is 
scarcely  tasted  at  the  tip,  but  is  tasted  immediately  on  the  back  part 
of  the  tongue. 

343.  Smell.  The  sense  of  smell  is  located  in  the  mem- 
brane which  lines  the  cavities  of  the  nose.  This  delicate 
membrane,  over  which  the  fibers  of 
the  olfactory  nerves,  or  the  nerves  of 
smell,  are  distributed,  is  kept  con- 
tinually moist  by  the  mucus  which 
it  secretes.  At  the  beginning  of  a 
cold  in  the  head  it  becomes  dry  and 
swollen,  and  the  sense  of  smell  may 
be  greatly  lessened. 

It   is  in  the  upper  parts  of  the 
nasal  cavities  that  the  sense  of  smell 

FIG.  153.    Nasal  Cavities,    is  most  ^^^     Hence,  when   we 
seen  from  Below.          wish  to  detect  a  faint  odor  we  sniff 

1  The  sense  of  smell  varies  very  much  in  different  individuals.  Among 
civilized  people  it  is  often  defective,  while  in  savage  races  it  is  notably 
acute.  We  are  told  that  the  South  American  Indians  can  detect  the 
approach  of  a  stranger,  even  on  a  dark  night,  by  their  sense  of  smell,  and 
can  also  tell  whether  he  is  white  or  black.  Many  animals  are  more  highly 
endowed  with  this  sense  than  man.  Thus,  a  dog  will  smell  the  footsteps 


THE   SPECIAL   SENSES 


251 


the  air  sharply.  The  sense  of  smell  seems  to  be  nature's 
sentinel  to  guard  us  against  taking  improper  food  into  the 
stomach  and  impure  air  into  the  lungs. 

Experiment  73.  To  show  that  we  often  fail  to  distinguish  between 
the  sense  of  taste  and  that  of  smell.  If  we  chew  some  pure  roasted 
coffee,  it  seems  to  have  a  distinct  taste.  Pinch  the  nose  hard  while 
chewing  it,  and  there  is  little 
taste.  Coffee  has  a  powerful 
odor  but  only  a  feeble  taste. 
The  same  is  true  of  garlic, 
onions,  and  various  spices. 

Experiment  74.  Light  helps 
the  sense  of  taste.  Shut  the 
eyes,  and  palatable  foods  taste 
insipid.  Pinch  the  nose,  close 
the  eyes,  and  see  how  palatable 
one  half  of  a  teaspoonful  of 
cod-liver  oil  becomes. 

Experiment  75.  Close  the 
nostrils,  shut  the  eyes,  and 
attempt  to  distinguish  by  taste 
alone  between  a  slice  of  an 
apple  and  one  of  a  potato. 


FIG.  154.  Distribution  of  Nerves  over 
the  Interior  of  the  Nostrils.  (Outer 
wall.) 

A,  branches  of  the  nerves  of  smell ;  B,  nerves 
of  touch  to  the  nostrils ;  E,  F,  G,  nerves 
to  the  palate  springing  from  a  ganglion  at 
C;  H,  a  branch  of  the  facial  nerve,  from 
which  other  branches,  D,  I,  and  /,  spring 
to  be  distributed  to  the  nostrils. 


344.  The  Sense  of  Hear- 
ing. We  come  now  to  a 
special  sense,  which  does 
not  tell  us  what  is  going 
on  in  the  outer  world  by 
actual  contact,  as  in  touch  or  taste,  nor  by  particles  of 
matter  falling  upon  the  ends  of  nerves,  as  in  the  sense 

of  his  master  amid  those  of  a  hundred  other  people,  and  can  track  him  for 
miles,  although  he  has  been  for  hours  out  of  sight.  Hounds  track  the 
fox  or  the  deer  by  the  sense  of  smell.  Dogfish  find  their  prey  by  the  sense 
of  smell  rather  than  by  sight. 


252 


OUR  BODIES  AND   HOW  WE   LIVE 


of  smell.    In  the  sense  of  hearing,  impressions  are  made  upon 
the  nerves  by  wavelike  vibrations  in  the  surrounding  air. 

All  sounds  are  caused  by  the  vibration  of  something  in 
the  atmosphere.  The  object  struck  sends  out  these  vibra- 
tions to  the  surrounding 
air,  which  carries  forward 
a  series  of  waves  in  all 
directions.1 

345.  The  Organ  of  Hear- 
ing. The  air  waves  are 
received,  and  the  impres- 
sion made  by  them  is  sent 
to  the  brain,  by  a  special 
apparatus,  called  the  organ 
of  hearing.  It  is  lodged  in 
the  temporal  bone,  one  of 
the  thick,  inner  bones  which 
form  the  base  of  the  skull. 
The  ear,  the  organ  of 
hearing,  is  far  more  com- 


FIG.  155.     The  Pinna,  or  Auricle. 


plicated  than  any  of  the  organs  of  sense  yet  described.  It 
is  second  only  in  importance  to  the  eye,  the  organ  of  sight. 

The  ear  is  divided  into  three  parts,  —  the  outer,  the  middle, 
and  the  inner  ear. 

346.  The  Outer  Ear.  The  outer  ear  consists  of  a  plate 
of  gristle,  shaped  somewhat  like  a  shell,  known  as  the  pinna, 

1  We  shall  understand  these  air  waves  better  if  we  throw  a  stone  into  a 
pool  of  water  and  watch  the  result.  We  see  a  series  of  tiny  circular  ripples 
gradually  spread  themselves  over  the  surface  of  the  water  from  the  spot 
where  the  stone  fell.  This  exactly  represents  the  waves  of  sound  caused 
by  the  vibration  of  bodies  in  the  air.  These  air  waves  travel  with  wonder- 
ful rapidity.  The  usual  velocity  of  sound  is  about  eleven  hundred  feet 
a  second. 


THE   SPECIAL  SENSES 


253 


or  auricle,  and  of  a  tube  about  an  inch  long,  called  the  audi- 
tory canal. 

The  auricle  is  used  as  a  kind  of  ear  trumpet  to  gather  up 
the  sound  waves.  Many  animals  are  able  to  move  the 
large  external  ear  in  the  direction  of  the  sound.  Thus,  the 
horse  and  the  rabbit  prick  up  their  ears  when  they  hear  a 
noise,  the  better  to  judge  of  the  direction  of  sounds. 

The  auditory  canal  is  a  passage  in  the  solid  portion  of  the 
temporal  bone.  It  is  lined  by  skin  on  which  there  are  fine 
hairs,  and  a  set  of  glands  secreting  earwax,  which  serves 
to  moisten  the  parts,  catch  particles  of  dust,  and  keep 
away  small  insects. 

The  inner  end  of  the  auditory  canal  is  closed  by  a  mem- 
brane stretched  tightly  across  it.  It  resembles  the  parch- 
ment stretched  across  the  end  of  a  drum,  and  is  known  as 
the  tympanic  membrane,  or  drum  membrane. 
It  is  thin  and  elastic,  but  may  be  broken 
by  a  blow,  or  by  pushing  some  sharp  or 
hard  substance  into  the  ear. 

347.  The  Middle  Ear.  The  middle  ear 
is  a  small,  drumlike  cavity, 
full  of  air,  in  the  temporal 
bone.  This  cavity  is 
known  as  the  drum  of  the 
ear,  or  tympanum.  On  the 
inner  wall  of  this  air  cham- 
ber are  two  small  openings, 
the  "oval  window"  and  the  "round  window,"  both  of  which 
are  closed  by  membranes.  The  most  curious  feature  of  the 
middle  ear  is  a  string  of  three  tiny  bones  which  stretch  across 
it.  These  bones  are  called  from  their  shape  the  hammer,  or 
malleus ;  the  anvil,  or  incus;  and  the  stirrup,  or  stapes. 


FIG.  156.    A  Cast 
of  the  External  Audi- 
tory Canal.      (Poste- 
rior view.) 


254  OUR   BODIES   AND   HOW  WE   LIVE 

The  hammer  bone  is  fastened  by  its  long  handle  to  the 
drum  membrane.  The  round  head  of  the  hammer  bone 
fits  into  the  anvil  bone.  Next  to  the  anvil  is  the  stirrup 
bone,  which  fits  into  the  little  oval  window  in  the  opposite 
wall  of  the  chamber  or  drum. 

348.  The  Eustachian  Tube.     In  the    floor  of  the  tym- 
panic cavity  is  the  opening  of  a  passage  called  the  Eusta- 
chian tube.     This  tube  is  about  an  inch  and  a  half  long,  and 
leads  into  the  back  part  of  the  throat.     It  allows  air  from 

the  throat  to  enter  the  drum,  and  serves 
to  keep  the  air  on  both  sides  of  it  at 
equal  pressure  (Fig.  69). 

During  a  severe  cold  in  the  head,  or 
a  sore  throat,  the  lining  of  the  tube  may 
be  inflamed  and  swollen.     This  gives 
FIG.  157.    The  Bones    a  stuffed  feeling  in  the  ears,  and  the 
of  the  Ear.  hearing  may  be  slightly  impaired.     As 

i,  malleus,  or   hammer;       tne  cold  paSSCS  off,  this  peculiar  feeling 
2,  incus,  or  anvil;   3, 

stapes,  or  stirrup.         m  the  ears  usually  disappears. 

Experiment  76.  To  produce  vibration  of  the  tympanic  membrane 
and  the  little  ear  bones.  Shut  the  mouth  and  pinch  the  nose  tightly. 
Try  to  force  air  through  the  nose.  The  air  dilates  the  Eustachian 
tube  and  is  forced  into  the  ear  drum.  The  distinct  crackle,  or  click- 
ing sound,  is  due  to  the  movement  of  the  ear  bones  and  the  tympanic 
membrane. 

349.  The  Inner  Ear.     The  inner  ear  is  a  bony  case  filled 
with  liquid  in  which  float  the  delicate  ends  of  the  nerve  of 
hearing.     It  consists  of  three  distinct  portions,  —  the  vesti- 
bule, the   semicircular  canals,  and  the  cochlea,  or  snail's  shell. 
It  is  enough  for  us  to  remember  that  these  are  winding 
channels  and  spiral  tubes  hollowed  out  in  the  solid  bone. 
The  whole  system  of  passages  is  known  as  the  labyrinth. 


THE   SPECIAL   SENSES 


255 


It  is  important  to  remember  that  there  is  a  continuous 
connection  between  all  the  passages  of  the  inner  ear,  and 
that  all  the  winding  tubes  and  chambers  inclose  and  pro- 
tect a  delicate  bag  of  membrane  of  exactly  the  same  shape 
as  themselves. 

350.  The  Au- 
ditory Nerve. 
The    auditory 
nerve,  or  nerve  of 
hearing,  passes 
to  the  brain, 
through  a  little 
hole  in  the  solid 
bone  of  the  skull, 
from  the  inner 
ear,  where  its 
nerve   fibers 

branch    round     FIG.  158.     General  View  of  the  Organ  of  Hearing. 

the  sense  cells 
on  the  inner 
walls  of  the  lin- 
ing membrane. 

351.  How  we 
Hear.      Let  us 
learn    a   few  of 

the  simplest  principles  about  this  wonderful  mechanism »of 
the  ear.  A  bell  is  rung  or  a  gun  fired.  The  vibration  is 
communicated  to  the  atmosphere  around  it,  and  passes  away 
in  air  waves  from  the  sounding  body,  as  the  waves  ripple 
the  surface  of  a  pond  after  a  stone  has  been  thrown  in. 

The  air  waves  pass  into  the  outer  ear  and  strike  upon 
the  stretched  membrane  of  the  drum,  causing  it  to  vibrate. 


A,  pinna ;  B,  cavity  of  the  concha,  showing  the  openings 
of  a  great  number  of  sebaceous  glands  ;  C,  external  audi- 
tory meatus;  £>,  tympanic  membrane  ;  F,  incus;  //,  mal- 
leus ;  K,  handle  of  malleus  applied  to  the  internal  surface 
of  the  membrana  tympani ;  Z,,  tensor  tympani  muscle ; 
between  M  and  K  is  the  tympanic  cavity ;  N,  Eusta- 
chian  tube ;  O,  P,  semicircular  canals ;  R,  internal  audi- 
tory canal;  S,  large  nerve  given  off  from  the  facial 
nerve ;  T,  facial  and  auditory  nerves. 


256 


OUR  BODIES  AND  HOW  WE   LIVE 


At  every  vibration  of  the  membrane  the  head  of  the  ham- 
mer bone  strikes  upon  the  anvil  bone,  drives  it  forward, 
and  pushes  the  foot  plate  of  the  stirrup  bone  in  and  out  of 
the  oval  window  on  the  inner  wall  of  the  chamber. 

The  waves  thus  formed  in  the  watery  fluid  in  the  inner 
ear  strike  against  the  membranous  bag,  and  so  arouse  a 
nervous  impulse  in  the  fibers  of  the  auditory  nerve.  The 

nerve  of  hearing  transmits  the 
auditory  impulses  from  the 
sense  cells  to  the  seat  of  sen- 
sation in  the  brain,  where  they 
are  interpreted  as  sounds. 

352.  Hints  on  the  Care  of 
the  Ear.  The  ear  canal  should 
never  be  rudely  or  hastily 
washed  out.  The  utmost  gen- 
tleness in  washing  out  the  ear 

FIG.  159.  Bony  Internal  Ear  of  is  all  that  is  necessary  for  clean- 
liness. The  ears  should  never 
be  pulled  or  boxed.  Even  a 
slight  blow  has  resulted  in 
serious  trouble. 

Never  use  earpicks,  ear 
spoons,  the  ends  of  pencils  or 
penholders,  pins,  hairpins,  toothpicks,  towel  corners,  etc., 
to*pick,  scratch,  or  cleanse  the  ear  canal.  It  is  a  foolish, 
needless,  and  dangerous  practice. 

Let  the  earwax  take  care  of  itself.  The  skin  of  the  ear 
grows  outward,  and  the  extra  wax  and  dust  will  be  naturally 
carried  out  if  let  alone.  Never  drop  sweet  oil,  glycerin, 
or  other  fluids  into  the  ear  with  the  idea  that  it  is  made 
cleaner  by  them.  They  often  cause  irritation. 


the  Right  Side. 

Magnified ;  the  upper  figure  of  the 
natural  size. 

A,  oval  window ;  ff,  C,  D,  semicircular 
canals ;  *  represents  the  bulging  part 
of  each  canal ;  E,  F,  G,  cochlea ;  H, 
round  window. 


THE   SPECIAL  SENSES 


257 


VESTIBULE  WITH  OPENINGS 
•OF  SEMICIRCULAR  CANALS 


Cotton  wads  may  be  put  into  the  ears  to  shield  them  from 
a  cold  wind,  or  may  be  worn  while  one  is  swimming  or  diving, 
to  keep  the  water  out.  Diving  into  deep  water  or  bathing 
in  the  breakers  may  injure  the  ears  if  not  thus  protected. 

353.  Additional  Suggestions  on  the  Care  of  the  Ears.  We 
should  never  shout  suddenly  in  a  person's  ear.  The  ear  is 
not  prepared  for  the  shock,  and  permanent  injury  has  occa- 
sionally resulted. 
If  theEustachian 
tube  is  closed 
for  the  time,  a 
sudden  explo- 
sion, the  noise  of 
a  gun  or  cannon, 
may  burst  the 
drumhead. 
Soldiers  during 
heavy  cannonad- 
ing open  the 
mouth  to  allow 
an  equal  tension  of  air  on  both  sides  of  the  membrane. 

Flies,  ants,  and  other  insects  sometimes  crawl  into  the 
ear.  This  may  cause  some  pain  and  fright,  and  perhaps 
lead  to  vomiting  and  even  convulsions  in  the  case  of  chil- 
dren. A  lighted  lamp  put  at  the  entrance  of  the  ear  will 
often  coax  insects  to  crawl  out  towards  the  light.  The  ear 
may  be  syringed  out  with  a  little  warm  water.  Drop  in  a 
little  sirup,  melted  vaseline,  or  sweet  oil. 

Cold  water  should  never  be  used  in  the  ears  or  nostrils 
if  it  can  be  helped.  Use  only  tepid  water.  Do  not  go  to 
sleep  with  the  head  in  any  position  that  may  expose  the 
ears  to  a  draught  of  cold  or  damp  air. 


-^^- EUSTACHIAN  TUBE 


FIG.  160.     BLACKBOARD  SKETCH. 
Diagram  of  the  Middle  and  Internal  Ear. 


258  OUR  BODIES   AND    HOW  WE   LIVE 

When  one  suffers  from  severe  or  continued  earache  it  is 
always  best  to  consult  a  physician.  In  the  meantime  some 
relief  may  be  obtained  by  holding  a  hot  sand  bag  or  hot- 
water  bottle  to  the  ear. 

354.  Effect  of  Alcohol  and  Tobacco  upon  Hearing.    Strong 
drink  tends  to  inflame  first  the  lining  membrane  of  the 
throat  and  then  that  of  the  Eustachian  tube.     The  inflam- 
mation may  spread  after  a  time  to  the  delicate  apparatus 
of  the  inner  ear. 

The  immoderate  use  of  tobacco  may  injure  the  sense  of 
hearing.  The  irritating  smoke,  filling  the  deeper  parts  of 
the  nose  and  throat,  easily  finds  its  way  through  the  Eusta- 
chian tube  and  tends  to  irritate  the  delicate  parts  of  the 
middle  ear. 

355.  The  Wonderful  Sense  of  Sight.     Sight  is  the  highest 
and  most  perfect  of  all  our  senses.     By  means  of  it  we  may 
follow  the  vessel  sailing  along  on  the  dim  horizon,  and  the 
next  instant  we  may  be  reading  the  fine  print  of  a  newspaper. 
By  means  of  this  sense  we  recognize  the  form,  size,  color, 
and  distance  of  thousands  of  different  objects  in  nature. 

The  sense  of  sight  is  so  woven  into  the  countless  acts  of 
our  everyday  affairs  that  we  scarcely  appreciate  this  mar- 
velous gift,  so  essential,  not  only  to  the  simplest  matters 
of  comfort,  but  also  to  the  culture  of  the  mind  and  the 
higher  forms  of  pleasure. 

356.  The  Eye.    The  eye,  the  outer  instrument  of  sight, 
is  a  most  beautiful  piece  of  mechanism.     This  little  organ, 
only  about  an  inch  in  diameter,  is  in  reality  one  of  the 
greatest  wonders  in  nature. 

The  eyeball  is  lodged  in  a  bowl-shaped  cavity  made  up 
of  seven  of  the  bones  of  the  head  and  face.  This  eye 
socket  is  well  protected  on  its  edges  by  the  dense  and 


THE   SPECIAL  SENSES 


259 


strong  bones  of  the  head,  and  is  padded  with  fat,  which  acts 
as  a  soft  elastic  cushion  for  the  eyeball. 

357.  The  Coats  of  the  Eye.  The  walls  of  the  eyeball  are 
made  up  of  three  distinct  coats,  or  coverings. 

The  outer  covering,  or  sclerotic,  is  one  of  the  toughest  and 
strongest  membranes  in  the  body,  and  serves  as  a  kind  of 


SUPERIOR  RECTUS 


SUSPENSORY  LIGAMENT 
CILIARY  PROCESSES 


CHOROID 


OPTIC  NERVE 


CHOROID 


-INFERIOR  RECTUS 
FIG.  161.     BLACKBOARD  SKETCH. 
Section  of  the  Human  Eye. 


elastic  framework  for  the  eye,  and  protects  the  delicate 
structures  within.  That  part  of  it  which  is  visible  is  known 
as  the  white  of  the  eye. 


260  OUR  BODIES  AND  HOW  WE  *LIVE 

This  outer  coat  of  the  eyeball  gives  place  in  the  front 
to  a  transparent  circular  plate,  just  as  in  a  watch  the  gold 
or  silver  case  gives  place  to  a  glass  crystal  over  the  face. 
This  transparent  plate,  the  cornea,  forms  a  kind  of  rounded 
bay  window  for  the  eye,  and  is  often  spoken  of  as  the 
window  of  the  eye. 

The  second  coat,  or  choroid,  is  much  more  delicate  in 
structure  and  consists  almost  entirely  of  blood  vessels  and 
nerves.  It  is  lined  with  a  thick,  black  coating  designed  to 
absorb  the  surplus  rays  of  light,  which  would  otherwise 
cause  blurred  or  confused  vision.  In  many  animals  the 
choroid  is  rich  with  colors;  hence  the  green  sheen  of  a 
cat's  eye. 

358.  The  Retina.    The  retina,  meaning  a  net,  the  inner- 
most coat  of  the  eyeball,  is  an  extremely  delicate  and  sen- 
sitive screen  upon  which  the  image  is  formed.     It  is  a  net 
of  fibers  proceeding  from  the  optic  nerve  and  spread  out 
over  the  inner  surface  of  the  eye. 

359.  The  Iris  and  Pupil.    To  get  a  clear  idea  of  the 
inner  parts  of  the  eye,  let  us  imagine  an  eyeball  cut  through 
the  middle  from  above  downwards.     Let  us  now  start  in 
front  and  go  backwards  (Fig.  161). 

We  shall  first  see  the  cornea,  which  has  just  been  described. 

We  now  reach  a  space  called  the  front  chamber  of  the 
eye.  In  this  chamber,  and  behind  the  cornea,  is  hung  a 
round  curtain,  the  iris,  meaning  rainbow.  It  is  pierced  by 
a  hole  through  its  center  for  the  admission  of  light.  This 
is  called  the  pupil,  which  appears  as  if  it  were  a  black  spot. 
It  is  this  curtain  which  gives  the  color  to  the  eye.  The 
iris  has  muscular  fibers  which  contract  and  relax,  and  thus 
make  the  pupil  larger  or  smaller,  according  as  the  light  is 
bright  or  dull. 


THE   SPECIAL  SENSES 


26l 


When  the  light  is  very  strong  and  brilliant  the  iris  spreads 
its  curtain  farther  over  the  pupil  in  order  to  shut  out  some 
of  the  rays.  When  the  light  is  faint  the  curtain  is  drawn 
back,  making  the  pupil  larger  in  order  to  admit  as  many 
rays  of  light  as  possible. 

The  black  appearance  of  the  pupil  is  due  to  the  thick 
black  coating  which  lines  the  inside  of  the  choroid  and  pre- 
vents all  light  from  passing  through  the  wall  of  the  eyeball. 
It  is  like  looking  through  a  small  window  into  a  dark  room. 


FIG.  162. 


Diagram  showing  the  Change  in  the  Lens  during 
Accommodation. 


On  the  right  the  lens  is  arranged  for  distant  vision,  the  ciliary  muscle  is  relaxed, 
and  the  ligament  D  is  tense,  so  flattening  by  its  compression  the  front  of  the 
lens  C;  on  the  left  the  muscle  A  is  acting,  and  this  relaxes  the  ligament  and 
allows  the  lens  B  to  become  more  convex,  and  so  fitted  for  the  vision  of 
near  objects. 

360.  The  Crystalline  Lens.  Just  behind  the  iris  is  a  clear, 
transparent,  jellylike  body,  called  the  crystalline  lens.  It  is 
convex,  or  rounded,  both  back  and  front,  and  is  about  one 
third  of  an  inch  in  diameter.  It  is  shut  up  in  a  kind  of 
transparent  bag  and  is  held  in  its  place  by  a  number  of 
little  bands.  The  crystalline  lens  separates  the  front 
chamber  of  the  eye  from  the  back  chamber. 

The  front  chamber  is  filled  with  a  clear,  watery  fluid 
called  the  aqueous,  or  watery,  humor,  This  fluid  keeps  the 


262  OUR   BODIES   AND   HOW  WE    LIVE 

cornea  uniformly  convex  and  allows  the  curtain  with  the 
hole  in  it  —  the  iris  —  to  float  and  move  at  freedom.  The 
back  chamber  contains  a  jelly  like  fluid  called  the  vitreous,  or 
glassy,  humor. 

361.  The  Course  of  the  Rays  of  Light  in  the  Eye.    Let 
us  now  master  a  few  points  about  the  mechanism  of  vision. 
Let  us  trace  the  course  of  the  rays  of  light  going  from  any 
luminous  body  —  a  lighted  candle,  for  example  —  through 
the  different  parts  of  the  eye.     Imagine  the  candle  to  be 
placed  about  ten  inches  in  front  of  the  eye. 

Some  of  the  rays  fall  on  the  outer  coat,  or  the  white, 
of  the  eye,  and,  being  turned  back  or  reflected,  take  no 
part  in  vision.  The  more  central  rays  fall  upon  the  cornea. 
Some  of  these  are  reflected,  giving  to  the  surface  of  the  eye 
its  beautiful,  glistening  appearance. 

Now,  if  the  rays  of  light  passed  directly  to  the  retina, 
they  would  pass  in  parallel  lines  and  produce  the  impres- 
sion of  light,  but  everything  would  be  dim  and  confused. 
Therefore  it  is  necessary  that  the  rays  coming  from  any 
object  should  be  brought  together  (converged)  by  being 
bent  (refracted).  That  is,  they  must  be  refracted  and 
brought  to  a  focus. 

362.  The  Work  done  by  the  Crystalline  Lens.    The  rays 
of  light  are  refracted  and  brought  to  a  focus  to  a  certain 
extent  by  the  cornea  and  the   fluids,  or  humors,  of  the 
eye,  but  mainly  by  the  crystalline  lens.     It  is  thus  the  duty 
of  the  crystalline  lens  to  bring  the  rays  of  light  nearer 
together  as  they  pass  through  it,  and  to  bring  them  to  a 
focus  on  the  retina. 

It  is  a  familiar  fact  in  the  use  of  optical  instruments  that 
they  must  be  differently  adjusted  for  objects  at  different 
distances.  The  boy  changes  the  focus  of  his  spyglass  by 


THE   SPECIAL   SENSES 


263 


OBJECT 


EYE 


pulling  its  tubes  in  or  out.  When  we  look  from  a  distant 
to  a  near  object  with  an  opera  glass,  we  change  the  focus 
by  turning  the  adjusting  screw. 

A  tiny  muscle  called  the  ciliary,  or  hairlike,  muscle  does 
for  the  eye  what  the  adjusting  screw  does  for  the  opera 
glass.  As  it  contracts  and  relaxes,  the  elastic  lens,  held 
in  place  by  a  delicate  membrane,  becomes  more  rounded 
or  flatter,  ac- 
cording as  we 
may  wish  to  look 
at  nearer  or  more 
distant  objects. 

In  other  words, 
our  eyes  adjust, 
or  accommodate, 
themselves  to 
the  varying  dis- 
tances of  objects, 
just  as  the  photographer  pushes  in  or  out  the  lens  of  his 
camera  so  as  to  bring  it  nearer  to  or  farther  from  the 
surface  which  receives  the  image  (Fig.  162). 

Experiment  77.  To  illustrate  accommodation.  Standing  near  a 
source  of  light,  close  one  eye  and  hold  up  both  forefingers  not  quite 
in  a  line,  keeping  one  finger  about  six  or  seven  inches  from  one  eye, 
and  the  other  forefinger  about  sixteen  or  eighteen  inches  from  the 
other  eye.  Look  at  the  near  finger ;  a  distinct  image  is  obtained  of 
it,  while  the  far  one  is  blurred  or  indistinct.  Look  at  the  far  image  ;  it 
becomes  distinct,  while  the  near  one  becomes  blurred.  Observe  that  in 
accommodating  for  the  near  object  one  is  conscious  of  a  distinct  effort. 

363.  Formation  of  an  Image  on  the  Retina.  The  rays  of 
light  are  thus  brought  to  a  focus  on  the  sensitive  retina. 
The  iris  has  regulated  with  wonderful  skill  the  proper 


FIG.  163.     BLACKBOARD  SKETCH. 

Diagram  illustrating  the  Manner  in  which  the  Image 
of  an  Object  is  inverted  on  the  Retina. 


264  OUR  BODIES  AND   HOW  WE   LIVE 

amount  of  light ;  and  the  lens,  with  the  greatest  exactness, 
has  focused  the  rays  on  the  retina.  The  dark  surface  of 
the  middle  coat  acts  to  absorb  the  excess  of  light,  the 
entrance  of  which  would  disturb  accurate  vision. 

As  a  result,  an  exact  but  inverted  image  is  formed  on  the 
retina.  The  impression  is  carried  to  the  brain  by  the  fibers 
of  the  optic  nerve,  which  are  spread  out  on  this  wonderfully 
sensitive  membrane. 

Experiment  78.  To  show  the  blind  spot.1  The  retina  is  not 
sensitive  where  the  optic  nerve  enters  the  eyeball.  This  is  called 
the  "  blind  spot."  Put  two  ink  bottles,  about  two  feet  apart,  on  a 
table  covered  with  white  paper.  Close  the  left  eye  and  fix  the  right 
steadily  on  the  left-hand  inkstand,  gradually  varying  the  distance  from 
the  eye  to  the  ink  bottle.  At  a  certain  distance  the  right-hand  bottle 
will  disappear,  but  nearer  or  farther  than  that  it  will  be  plainly  seen. 

364.  The  Muscles  of  the  Eye.  The  eyeball  is  rolled  and 
moved  about  by  six  muscles.  They  spring  from  the  back 
part  of  the  bony  orbits  and  are  fastened  to  the  front  part  of 
the  eyeball  by  means  of  tendons.  Four  of  these  muscles 
(the  recti,  or  straight,  muscles)  move  the  eye  up  or  down, 
and  to  the  right  or  left.  The  other  two  (the  oblique)  are 
so  fastened  that  they  rotate  the  eyeball  in  one  direction 
or  another.  If  the  eye  muscles  are  not  properly  balanced 
in  their  action,  squinting  results. 

1  The  location  of  the  blind  spot  may  be  shown  in  the  following  simple 
manner.  The  left  eye  being  shut,  let  the  right  eye  be  fixed  on  the  cross 
below.  When  the  book  is  held  at  arm's  length  both  cross  and  round  spot 


will  be  visible ;  but  if  the  book  be  brought  to  about  eight  inches  from  the 
eye,  the  gaze  being  kept  steadily  upon  the  cross,  the  round  spot  will  at  first 
disappear,  but  as  the  book  is  brought  still  nearer  both  cross  and  round  spot 
will  again  be  seen. 


THE   SPECIAL  SENSES 


265 


365.  The  Eyelids  and  Eyebrows.  The  eyes  are  protected 
and  kept  clean  by  their  eyelids,  eyelashes,  and  eyebrows. 

The  eyelids  are  thin,  flexible  covers,  or  shutters,  which 
protect  the  front  of  the  eyeballs.  They  are  composed  on 
the  outside  of  skin,  which  is  stiffened  at  the  margin  by  thin 
plates  of  gristle.  They  are  lined  on  the  inner  side  with 
a  very  delicate  mucous  membrane  called  the  conjunctiva, 


FIG.  164.     Muscles  of  the  Eyeball. 

A,  attachment  of  tendon  connected  with  the  four  recti  muscles ;  £,  exfernal 
rectus,  divided  and'turned  downward,  to  expose  the  internal  rectus;  C,  in- 
ferior rectus ;  Z),  internal  rectus  ;  £,  superior  rectus ;  f,  superior  oblique ; 
//,  pulley  and  reflected  portion  of  the  superior  oblique  ;  K,  inferior  oblique ; 
L  and  M,  portions  of  the  muscle  which  raises  the  upper  eyelid ;  to  the  right 
of  D  and  to  left  on  same  line  are  seen  cut  ends  of  the  optic  nerve. 

because  it  is  also  joined  to  the  eyeball  by  a  fold.  It  pours 
out  fluid  to  prevent  friction  between  the  surfaces.  This 
fluid,  together  with  the  tears,  which  are  constantly  flowing, 
keeps  the  cornea  moist  and  free  from  dust. 

The  edges  of  the  eyelids  are  provided  with  a  fringe  of 
fine  hairs,  the  eyelashes,  which  shade  the  eye  and  shield  it 
from  dust. 


266 


OUR   BODIES  AND   HOW  WE    LIVE 


The  eyebrows  form  a  protecting  and  shading  ridge  over 
the  eyes,  while. the  thick  fringe  of  hairs,  arranged  some- 
what like  the  straw  on  a  thatched  roof,  prevents  the  per- 
spiration from  rolling  into  the  eyes  as  it  trickles  down  the 

forehead. 

366.  The  Tears. 
Nature  provides  a 
special  fluid  to  pro- 
tect the  eye.  This 
fluid  is  call  ed  the 
tears. 

The  tear  apparatus 
consists  of  the  glancl 
for  secreting  a  thin, 
watery  fluid,  the 
tears,  and  the  pas- 
sages for  draining 
them  off.  The  tears 
moisten  the  surface 
of  the  eye  whenever 
the  lids  wink,  and 
wash  away  the  par- 
ticles of  dust. 

The  tears  are 
carried  off  by  two 
fine  tubes,  one  in  the 
upper  and  one  in  the 
lower  lid,  which  unite 
and  form  a  sac  from  which  the  tear  duct  leads  into  the  nose. 
The  ordinary  flow  of  tears  is  thus  drained  off. 

Emotion  may  excite  an  excessive  flow  which  the  canals 
cannot  carry  off.  The  tears  then  overflow  and  run  down 


FTG.  165.     The   Relative   Position   of  the 
Lachrymal  Apparatus  and  the  Eyelids. 

A  and  C,  lachrymal  canals;  B,  lachrymal  sac; 
D,  small  muscle  which  serves  to  compress  the 
lachrymal  sac;  E,  lining  membrane  of  the  upper 
and  iower  eyelids;  F,  glands  upon  the  inner 
surface  of  the  eyelids,  with  ducts  opening  upon 
the  free  margins  of  the  eyelids ;  H,  great  open- 
ing, or  antrum,  of  the  upper  jawbone.  The  oil 
glands  of  the  nose  are  plainly  shown. 


THE    SPECIAL   SENSES 


267 


the  cheeks.  This  is  called  crying  or  weeping.  The  tears 
can  be  made  to  flow  in  a  reflex  way  by  almost  any  violent 
stimulation,  as,  for  example,  by  irritation  of  the  nasal  pas- 
sages by  pepper. 

367.  Color  Blindness.  The  inability  to  distinguish  between 
certain  colors  is  called  color  blindness.  It  is  sometimes  pro- 
duced by  sickness,  but  it  may  exist  at  birth  and  is  often 
hereditary.  It  is  in- 
curable. 

This  defect  of  sight 
is  quite  common.  Out 
of  the  many  thousands 
that  have  been  exam- 
ined, it  is  found  that 
four  men  out  of  every 
hundred  are  lacking 
in  the  power  to  dis- 
tinguish between  cer- 
tain colors.  Total 
color  blindness  is  very 
rare. 

A  person  who  is 
color  blind  cannot 
match  colors.  He  may 
pick  up  red,  brown, 
and  orange  wools  and 
match  them  with 
green  of  different  shades.  A  person  may  be  color  blind  and 
not  know  it  until  the  defect  is  accidentally  revealed. 

This  defect  of  vision  is  a  matter  of  the  utmost  prac- 
tical importance  to  those  employed  on  electric  and  steam 
railways,  vessels,  and  other  places  where  colored  signals 


FIG.  1 66.  The  Relative  Position  of  the 
Lachrymal  Apparatus,  the  Eyeball,  and 
the  Eyelids. 

A,  lachrymal  canals,  with  the  minute  orifices 
represented  as  two  black  dots  to  the  right; 
B,  tendon  attached  to  a  muscle  which  sur- 
rounds the  circumference  of  the  orbit  and  eye- 
lids ;  under  B  is  seen  the  kchrymal  sac.  The 
minute  openings  of  the  Meibomian  glands  are 
seen  on  the  free  margins  of  the  eyelids.  Below 
A  is  seen  a  small  conical  elevation,  with  black 
dots  (the  lachrymal  papilla,  or  caruncle). 


268 


OUR   BODIES   AND    HOW  WE    LIVE 


are  used.     The  most  common  forms  of  color  blindness  are 
those  in  which  one  fails  to  distinguish  red  from  green. 

368.  Near  Sight.     Near  sight   is  a  common  defect  of 
vision.     In  the  healthy  eye  the  rays  of  light  are  brought 
to  a  focus  on  the  retina.     But  in  some  eyes  the  image  is 
blurred ;  the  outer  coat  bulges  backward,  making  the  eye- 
ball a  little  too  long,  thus 
bringing  the  rays  of  light  to 
a  focus  before  they  reach  the 
retina.     A  person  is  said  to 
be  nearsighted  because  he 
can  see  near  objects  better 
than  those  at  a  distance. 

Nearsightedness  may  exist 
at  birth  and  is  often  heredi- 
tary. It  is  sometimes  ac- 
quired by  overstraining  the 
eyes  in  reading  too  fine  print, 
by  reading  by  a  dim  or  im- 
perfect light,  and  in  many 
other  ways.  This  defect  is 
common  with  those  who  use 


FIG.  167.     Lachrymal  Gland  and 
Ducts. 


A,  lachrymal  gland,  the  size  of  a  small 
almond,  lodged  in  the  upper  and  outer 

part  of  the  orbit ;  B,  lachrymal  ducts,    their  eyes  much  in  reading, 

which  form  a  row  «>f  openings  into  the     writing   and  studv>       Sailors, 
conjunctival  fold.  * 

farmers,  and  others  who 
work  outdoors  are  rarely  nearsighted. 

There  has  been  found  to  be  a  steady  increase  of  near- 
sightedness,  especially  among  school  children.  This  defect 
of  vision  calls  for  skillful  advice  and  careful  treatment. 

369.  Long  or  Far  Sight.  A  farsighted  person  is  so 
called  because  he  can  see  distant  objects  more  easily  than 
those  near  by.  In  a  long-sighted  person  the  eyeball  is  too 


THE   SPECIAL   SENSES 


269 


short  and  the  retina  lies  too  near  the  lens.  In  order  to 
see  near  objects  the  little  ciliary  muscle  must  be  put  to 
a  severe  strain  to  make 
the  lens  convex  enough. 
Thus  it  happens  that  the 
eye  of  a  long-sighted  per- 
son is  usually  under  a 
strain  when  working. 


U 


This  leads  to  headache 
and    fatigue.     In    child- 


FIG.  1 68.     Diagram  illustrating  the 
Nearsighted  Eye. 


hood  this  Strain  may  paSS     The  image  P'  of  a  distant  point  P  falls  in  front 
,  .        ••   £  . .     "      i  of  the  retina  even  without  accommodation. 

unnoticed  for  a  time,  but 


By  means  of  a  concave  lens  (Z,)  the  image  may 
be  made  to  fall  on  the  retina  (dotted  lines).  To 
save  space  P  is  placed  much  too  near  the  eye. 


sooner  or  later  it  shows 
itself  by  a  sense  of 
fatigue,  dizziness,  and  blurred  and  indistinct  vision. 

370.  How  the  Eyes  may  be  abused  in  Reading.  The 
habit  of  reading  the  daily  papers,  with  their  blurred  and 
indistinct  type,  in  a  steam  or  electric  car  or  in  a  carriage, 
is  a  severe  strain  on  the  eyes.  The  small  type,  poor  paper, 

and  presswork  of  the 
many  cheap  editions  of 
popular  books  are  very 
frequent  causes  of  weak 
and  diseased  eyes.  It  is 
a  dangerous  practice  to 


FIG.  169.     Diagram  illustrating  the 
Farsighted  Eye. 


The  image  /"of  a  point  P  falls  behind  the  retina     read  in   bed   at   night,  Or 
in  the  unaccommodated  eye.     By  means  of  a    while     j    •  f 

convex  lens  (L)  it  may  be  focused  on  the  retina  < 

without  accommodation  (dotted  lines).     To     Or  lounge  in   a  darkened 
save  space  P  is  placed  much  too  near  the  eye. 


cles  of  the  eyeball  are  put  to  a  great  deal  of  strain. 

371.  Proper  Light  and  Good  Eyesight.    The  direction  from 
which  the  light  comes  is  an  important  matter.    The  worst 


2/0 


OUR  BODIES.  AND   HOW  WE   LIVE 


direction  of  all  is  that  from  the  front.  The  direct  light 
should  fall  upon  the  print  from  above  and  from  the  left 
side.  The  more  nearly  an  artificial  light  resembles  mel- 
low daylight,  the  better.  A  flickering  light  is  always  bad. 

Artificial  light  should  be 
regulated  by  shades  and 
globes.  Recently  invented 
round  and  hollow  burners 
used  with  kerosene  oil  give 
an  excellent  light. 

Using  the  eyes  at  dusk, 
or  by  artificial  light  in  the 
early  morning,  may  lead  to 
serious  disorders  of  vision. 
The  light  reflected  from 
snow  is  a  common  source 
of  injury  to  the  eyes.  The 
eyes  of  infants  should  not 
be  exposed  to  the  glare  of 
electric  lights  or  to  the  direct  rays  of  the  sun. 

372.  Importance  of   Rest  for  the  Eyes.     After  reading 
steadily  for  some  time  we  should  rest  the  eyes  by  looking 
at  some  distant  object,  even  if  only  for  a  few  moments. 
A  person  should  never  read,  write,  sew,  or  otherwise  use 
the  eyes  when  they  tingle  or  smart,  or  when  the  sight  is 
dim  or  blurred.     The  eyes  are  weary  and  need  a  rest. 

The  eyes  are  often  weak  after  certain  sicknesses.  A 
long  rest  should  be  given  them  after  an  attack  of  measles 
or  scarlet  fever. 

373.  Additional  Hints  for  taking  care  of  the  Eyes.     The 
eyes  should  never  be  rubbed,  particularly  when  they  have 
been  irritated  by  some  foreign  substance.     The  sooner  it 


FIG.  170. 

Showing  the  attachment  of  the  recti,  or 
straight  muscles  to  the  eyeball,  also 
the  distribution  of  arteries  upon  the 
outer  coat  of  the  eye. 


THE   SPECIAL   SENSES 


271 


is  removed,  the  better.  Rubbing  the  eyes  or  pulling  the 
eyelids  only  makes  a  bad  matter  worse.  When  the  eyes 
smart  or  tingle,  after  going  to  bed,  and  are  bloodshot  on 
getting  up  the  next  morning,  it  is  safe  to  conclude  that 
they  have  been  irritated  or  overtaxed,  and  need  rest.  Rid- 
ing against  the  wind,  especially  on  a  bicycle  or  in  an  auto- 
mobile, is  often  hurtful,  at  least  for  eyes  that  are  inclined 
to  weakness  or  any  form  of  inflammation. 

It  is  not  a  wise  economy  to  tamper  with  one's  eyes  when 
they  are  ailing.  Better  to  do  nothing  than  do  the  wrong 
thing.  If  a  few  days  of 
rest  do  not  give  relief,  a 
good  oculist  should  be 
consulted  at  once. 

374.  Effect  of  Alcohol 
on   Sight.      The   govern- 
ment coast  survey  every 

summer  employs  several  small  companies  of  men  in  meas- 
uring distances  from  high  points  along  the  coast.  It  has 
been  found  by  experience  that  whenever  these  men  indulge 
in  strong  drink  their  work  is  often  impaired  and  faulty. 
They  fail  to  signal  correctly  or  to  be  accurate  in  their 
own  records. 

375.  Effect  of  Tobacco  on  Sight.   A  personal  examination, 
conducted  by  Dr.  Francis  Bowling,  of  about  ten  per  cent 
of  the  employees  of  a  Cincinnati  factory  employing  fifteen 
hundred  men  showed  many  of  the  men  who  used  tobacco, 
either  chewing  or  smoking,  to  be  suffering  from  a  gradual 
failure   of  vision.     With  one   exception,  the  women   em- 
ployees of  the  same  factory  who  were  examined  by  him 
gave  no  evidence  of  tobacco  poisoning  as  manifested  by 
troubles  of  vision. 


FIG.  171.  The  Actual  Size  of  the 
Test  Type,  which  should  be  seen 
by  the  Normal  Eye  at  a  Distance 
of  Twenty  Feet. 


2/2  OUR  BODIES  AND   HOW  WE  LIVE 


QUESTIONS   ON  THE  TEXT 

I.  What  is  meant  by  a  stimulus?     2.  What  can  be  said  about 
general  sensations?     Illustrate.     3.  From  what  do  most  sensations 
result?     Illustrate.     4.  What  are  the  special  senses?     5.  What  are 
the  special  sense  organs  ?     6.   Describe  the  sense  of  touch.     7.  What 
can  you  say  about  sensations  of  heat  and  cold?     8.  Describe  in 
full  the  sense  of  taste.     9.  Where  is  the  sense  of  smell  located? 
10.  What  general  difference  is  there  between  the  sense  of  hearing 
and  that  of  touch,  taste,  or  smell? 

II.  What  is  the  organ  of  hearing,  and  what  are  its  three  general 
parts  ?     12.  Describe  the  outer  ear.     13.  What  is  the  tympanic  mem- 
brane?    14.  Describe  the  middle  ear.     15.  Give  some  details  about 
the  bones  of  the  ear.     16.  What  is  the  Eustachian  tube  ?     17.  What 
is  the  inner  ear?     18.  Describe  the  three  parts  of  the  inner  ear. 
19.  Describe  the  auditory  nerve.     20.  Explain  in  some  detail  how  we 
hear. 

21.  Give  some  practical  points  about  the  care  of  the  ears.  22.  What 
is  the  general  effect  of  alcohol  and  tobacco  upon  hearing  ?  23.  What 
may  be  said  in  a  general  way  about  the  sense  of  sight?  24.  What  is 
the  eye,  and  where  is  the  eyeball  lodged?  25.  Describe  the  coats  of 
the  eye.  26.  What  is  the  retina  ?  27.  Describe  the  iris  and  the  pupil. 
28.  What .  is  the  crystalline  lens  ?  29.  What  are  the  two  fluids,  or 
humors,  of  the  eye?  30.  Describe  the  work  done  by  the  crystalline 
lens. 

31.  Describe  in  some  detail  the  mechanism  of  vision.  32.  How  is 
the  image  formed  on  the  retina?  33.  Describe  the  muscles  of  the 
eye,  and  explain  their  action.  34.  Describe  the  eyelids,  and  explain 
how  they  are  kept  moist.  35.  What  are  the  eyelashes  and  the  eye- 
brows ?  36.  What  are  the  tears,  and  of  what  does  the  tear  apparatus 
consist  ?  37.  What  is  color  blindness  ?  38.  What  is  meant  by  near 
sight?  39.  Explain  what  is  meant  by  long  or  far  sight.  40.  How 
may  the  eyes  be  abused? 

41.  What  is  the  relation  of  proper  light  to  good  eyesight  ?  42.  Why 
is  rest  of  great  importance  to  the  eyes?  43.  Give  some  practical 
hints  about  taking  care  of  the  eyes.  44.  What  is  the  general  effect 
of  alcohol  on  sight?  45.  How  may  tobacco  affect  the  sight? 


CHAPTER  XII 
THE  THROAT  AND  THE  VOICE 

376.  The  Throat.    The  throat  is  the  common  highway,  as 
it  were,  through  which  food  goes  to  the  stomach  and  air  to 
the  lungs. 

We  have  already  learned  something  of  the  food  passages 
(Chapter  VI)  and  the  air  passages  (Chapter  VIII),  and 
we  are  familiar  with  the  hard  palate,  the  soft  palate,  the 
uvula,  and  the  tonsils  (Figs.  63  and  69). 

377.  The  Pharynx.     The  only  way  to  get  a  proper  idea 
of  the  throat  is  to  look  into  a  friend's  mouth.     First,  let 
the   person   hold   his    mouth    wide    open,    facing  a    good 
light.     Hold  the  tongue  down  with  the  handle  of  a  spoon 
(Fig.  63). 

On  looking  directly  into  the  back  of  the  mouth  we  see 
the  beginning  of  a  passage  called  the  pharynx,  which  is  com- 
mon to  the  two  highways,  or  passages  by  which  air  and 
food  are  taken  into  the  body.  If  we  look  at  the  top,  we 
see  the  air  passage  which  leads  to  the  nose.  The  air  tract 
at  the  top  of  the  pharynx  has  two  outlets,  the  mouth  and 
the  nose. 

Now,  if  we  pull  the  tongue  firmly  forward,  a  little  curved 
ridge  is  sometimes  seen  behind  it.  This  is  the  epiglottis, 
which,  as  we  already  know,  is  the  trapdoor  that  shuts  down, 
like  the  lid  of  a  box,  over  the  top  of  the  air  passage,  or 
windpipe  (Sec.  153). 

273 


2/4 


OUR   BODIES   AND   HOW  WE   LIVE 


The  part  of  the  throat  directly  opposite  the  line  of  vision, 
as  we  have  learned,  is  the  back  wall  of  the  pharynx,  which 
continues  downward  to  form  the  gullet,  or  food  passage. 
The  pharynx  runs  up  to  the  base  of  the  skull  behind, 
and  ends  in  a  kind  of  vaulted  roof 
bent    somewhat    like    a    crooked 
forefinger. 

Experiment  79.  Study  the  general 
construction  of  the  throat  by  the  help 
of  a  hand  mirror.  Also  examine  the 
throat  of  some  friend. 

Experiment  80.  To  show  the  con- 
struction of  the  vocal  organs.  Secure 
and  examine  the  windpipe  of  a  sheep 
or  a  calf.  It  differs  somewhat  from 
the  vocal  organs  of  the  human  body, 
but  it  will  enable  us  to  recognize  the  dif- 
ferent parts  which  have  been  described. 
A  suitable  specimen  can  easily  be  ob- 
tained from  a  butcher. 


FIG.  172.     BLACKBOARD 
SKETCH. 

Diagram  of  a  Sectional  View 
of  Nasal  and  Throat  Pas- 
sages. 


378.  Care  of  the  Throat.  Ex- 
posed as  it  is  to  overheated  and 
unwholesome  air,  the  irritating 
dust  of  the  street  and  the  work- 
shop, and  extremes  of  heat  and 
cold,  it  is  not  strange  that  the 


C,  nasal  cavities;  T,  tongue; 
L,  lower  jaw ;  M,  mouth  ;  £/, 
uvula ;  £.  epiglottis ;  G,  lar-  ,  •>  •  i  •  •  r  ,-t  .1  r 

ynx;  o,  gullet,  or  oesophagus,    delicate  lining  of  the  throat  often 
becomes  inflamed.     The  result  is 
"sore  throat."    Almost 


an  ailment  which  is  commonly  called 
everybody  has  at  times  suffered  from  it. 

Persons  subject  to  sore  throat  should  take  great  pains 
to  wear  proper  underclothing.      Daily  baths  are  excellent 


THE  THROAT  AND  THE  VOICE 


275 


tonics  to  the  skin,  and  thus  serve  indirectly  to  harden  one 
who  is  liable  to  throat  ailments  even  in  ordinary  changes 
in  the  weather. 

Muffling  the  neck  in   scarfs,   furs,  and  wraps   is  not  a 

good  plan,  —  it  only  increases  the  liability  to  catch  cold, 

—  except,    perhaps,    during    the 

coldest  weather  or  during  unusual 

exposure  to  cold. 

379.  The  Larynx.  As  we  have 
been  told  in  a  preceding  section, 
the  boxlike  top  of  the  windpipe  is 
called  the  larynx,  meaning  top  of 
the  windpipe  (Sec.  222). 

The  sides  of  this  box  are  made 
of  two  flat  pieces  of  cartilage 
shaped  like  a  shield  and  known 
as  the  thyroid  cartilage.  The 
edges  unite  in  front  and  project 
to  form  "  Adam's  apple,"  which  FIG.  173. 
is  easily  felt  and  is  plainly  to  be 
seen  on  most  lean  people,  espe- 
cially spare  men  (Exp.  33,  p.  109). 
The  thyroid  cartilage  shelters  the 
delicate  and  movable  structure 
within  and  shields  it  from  injury 
from  without. 

The  epiglottis  is  attached  to  the 
inner  and  upper  part  of  this  carti- 
lage. Just  below  is  a  ring-shaped 
cartilage  called  the  cricoid.  It  is  broad  behind,  quite  narrow 
in  front,  much  like  a  seal  ring.  This  is  easily  detected 
under  the  skin,  a  little  below  "  Adam's  apple." 


Cartilages  and  Liga- 
ments of  the  Larynx.  (Front 
view.) 

A,  hyoid  bone;  B,  membrane  at- 
tached to  hyoid  bone  and  the 
shield-shaped  cartilage  below 
(thyroid);  edges  of  this  shield- 
shaped  cartilage  unite  at  C 
(Adam's  apple  is.  the  V-shaped 
groove  on  a  line  with  B  and  C) ; 
D,  membrane  between  the 
shield-shaped  cartilage  and  the 
signet-ring  cartilage  below;  E, 
cricoid,  or  signet-ring,  cartilage  ; 
F,  upper  ring  of  the  windpipe. 


276 


OUR  BODIES  AND   HOW  WE  LIVE 


Two  slender,  ladle-shaped  cartilages  are  placed  on  the 
top  of  the  back  part  of  the  cricoid.  They  work  with  a 
ball-and-socket  joint  and  have  tiny  muscles  which  regulate 
^r-r->^  their  movements  with  the  utmost 

accuracy. 

380.  The  Vocal  Cords.  From 
each  of  the  two  ladle-shaped  carti- 
lages a  band  of  elastic  tissue  passes 
forward  and  is  joined  to  the  inner 
and  front  part  of  the  shieldlike 
cartilage  towards  its  lower  edge. 
These  two  bands,  called  the  vocal 
cords,  are  narrow  strips  of  firm, 
fibrous  material  with  a  chinklike 
opening  between  them  called  the 
glottis,  meaning  the  mouthpiece  of 
a  flute.  These  cords  are  the  real 
organ  of  voice. 

All  the  air  which  goes  out  of  or 
into  the  lungs  must  go  through  the 
glottis.  There  are  muscles  and 
cartilages  which  serve  to  tighten 
or  loosen  these  cords.  During 
ordinary  breathing  the  vocal  cords  are  widely  separated. 
381.  How  the  Voice  is  produced.  If  the  air  is  driven  out 
of  the  lungs  by  an  act  of  expiration  when  the  cords  are 
in  a  state  of  tension,  they  vibrate  and  produce  the  sound 
called  the  voice. 

The  different  musical  sounds  produced  in  singing  depend 
upon  the  length  and  the  varying  degree  of  tension  of  the 
vocal  cords.  The  compass  of  the  voice  depends  upon  the 
extent  to  which  the  variations  can  take  place.  A  practiced 


FIG.  174.  Cartilages  and 
Ligaments  of  the  Larynx. 
(Posterior  view.) 

A,  epiglottis ;  B,  thyroid  carti- 
lage ;  C,  ladle-shaped  carti- 
lage; JS,  cricoid  cartilage; 
F,  upper  ring  of  the  wind- 
pipe. 


THE   THROAT  AND   THE  VOICE 


277 


singer  can,  at  will,  give  the  requisite  tension  for  the  pro- 
duction of  any  particular  note. 

The  quality  of  a  voice  depends  chiefly  upon  the  shape 
of  the  larynx  and  of  the  other  air  passages  above  it.  In 
women  and  children  the  larynx  is 
smaller,  and  the  vocal  cords  shorter, 
than  in  men ;  consequently  their  voices 
have  a  higher  pitch.  The  larger  the 
larynx  and  the  longer  the  .cords,  the 
deeper  the  voice. 

Voice  may  exist  without  speech,  as 
in  many  animals.  Speech  is  the  voice 
modified  by  the  throat,  teeth,  palate, 
nose,  tongue,  and  lips. 

NOTE.  —  The  limitations  of  a  text-book 
on  physiology  for  elementary  schools  do  not 
permit  so  full  a  description-  of  the  voice  as 
the  subject  deserves.  For  additional  details 
the  student  is  referred  to  more  advanced 
text-books  or  to  some  small  manual  on  the 
subject,  as  Cohen's  The  Throat  and  the 
Voice,  a  volume  in  the  American  Health 
Primer  Series. 

Experiment  81.  Pinch  the  nostrils  and  try 
to  pronounce  slowly  the  words  "  Lincoln," 
"  something,"  or  any  other  words  which  re- 
quire the  sound  of  m,  In,  ng. 

This  will  illustrate  somewhat  crudely  the 
importance  of  the  resonating  cavity  of  the 
nose  in  articulation. 

Experiment  82.  Take  two  strips  of  India 
rubber  and  stretch  them  over  the  open  end 
of  a  boy's  bean  blower,  or  any  kind  of  tube. 
Tie  them  tightly  with  thread  so  that  a  chink 
will  be  left  between  them,  as  in  Fig.  1 76. 


FIG.  175.  Arrangement 
of  the  Vocal  Cords. 

A,  epiglottis ;  B,  section  of 
hyoid  bone ;  C,  false  vo- 
cal cords  which  have 
nothing  to  do  with  the 
production  of  voice;  Z>, 
oblong  opening  between 
the  false  and  true  vocal 
cords;  E,  true  vocal 
cord;  F,  section  of  the 
thyroid  cartilage;  H, 
section  of  anterior  por- 
tion of  the  cricoid  car- 
tilage; K,  trachea;  L, 
section  of  the  posterior 
portion  of  the  cricoid  car- 
tilage; M,  ladle-shaped 
cartilage. 


278  OUR  BODIES   AND   HOW  WE   LIVE 

To  illustrate  roughly  the  passage  of  air  through  the  glottis,  force 
the  air  through  such  a  tube  by  blowing  hard,  and  if  the  strips  are 
not  too  far  apart  a  sound  will  be  produced.  The  sound  will  vary  in 
character  according  as  the  bands  are  made  tight  or  loose. 

382.  Effect  of  Tobacco  upon  the  Throat  and  Lungs.    The 
effect  of  tobacco  upon  the  throat  and  lungs  is  frequently 
marked  and  persistent.     The  smoke  is  an  irritant,  both  by 
its  temperature  and  from  its  destructive  ingredients.     It 
irritates  and  dries  the  mucous  membrane  of  the  mouth  and 

throat,  producing  an  unnatural  thirst,  which  may 
excite  a  craving  for  intoxicating  liquors. 

The  irritation  of  the  throat  may  extend  up  the 
Eustachian  tubes  and  impair  the  hearing. 

Again,  the  breathing  in  of  the  poisonous  smoke 
produces  unhealthful   effects    upon   the   delicate 
mucous  membrane  of  the  bronchial  tubes  and  of 
FIG  i  6     ^e  lun&s<     Upon  the  former  it  often  produces 
an  irritating  cough,  with  short  breath.     The  pul- 
monary membrane  may  be   congested ;   taking  cold  then 
becomes  easy,  and  recovery  from  it  is  tedious. 

The  habit  of  inhaling  tobacco  smoke,  so  common  with 
boys  who  smoke  cigarettes,  and  then  forcing  it  through 
the  nostrils,  often  causes  inflammation  of  the  air  passages, 
throat,  and  nose.  Breathing  air  laden  with  tobacco  smoke 
may  irritate  and  inflame  the  throat.  Cigarette  smoking 
itself  is  irritating  to  the  throat  passages. 

383.  Effect  of  Alcohol  and  Tobacco  upon  the  Voice.    The 
peculiar  harsh  tone  of  the  voice  in  those  given  to  strong 
drink  is  a  familiar  fact.     The  reason  for  it  is  plain.     Alco- 
holic liquors  inflame  and  irritate  the  delicate  lining  of  the 
throat  and  of  the  vocal  cords.     This,  after  a  time,  may 
make  the  mucous  membrane  lining  thick  and  rough. 


THE   THROAT  AND   THE   VOICE  279 

Alcohol  may  weaken  the  vocal  efforts.  Hence,  vocalists, 
clergymen,  and  public  speakers  often  find  that  alcoholic 
drinks  impair  the  voice. 

Tobacco  affects  the  vocal  cords  and  to  a  marked  degree 
may  injure  the  voice.  In  fact,  our  best  teachers  of  vocal 
music  do  not  allow  their  pupils  to  use  alcoholic,  liquors 
and  tobacco.1 

1  The  celebrated  throat  doctor,  the  late  Sir  Morell  Mackenzie,  of 
London,  strongly  objected  to  cigarettes.  These  are  his  words: 

"  Cigarette  smoking  is  the  worst  form  of  tobacco  indulgence,  from  the 
fact  that  the  very  mildness  of  its  action  tempts  people  to  smoke  nearly  all 
day  long,  and  by  inhaling  the  fumes  into  their  lungs  saturate  their  blood 
with  the  poison.  It  should  be  borne  in  mind  that  there  are  two  bad  quali- 
ties contained  in  the  fumes  of  tobacco.  One  is  poisonous  nicotine,  the 
other  the  high  temperature  of  the  burning  tobacco." 

When  tobacco  is  smoked  there  are  developed  certain  acrid  vapqrs 
which  have  an  irritant  action  on  the  mouth  and  throat.  The  effects  of  smok- 
ing are  in  part  due  to  irritant  matters  in  the  smoke.  The  inflammation 
often  extends  to  the  larynx,  or  may  spread  up  the  Eustachian  tubes  and 
impair  the  hearing.  Cigarettes  are  especially  apt  to  cause  these  symp- 
toms. Those  who  draw  the  smoke  into  their  lungs  often  suffer  from 
chronic  inflammation  of  the  bronchial  tubes  in  consequence.  —  H.  NEWELL 
MARTIN,  M.D. 

QUESTIONS  ON  THE  TEXT 

1.  What  is  the  throat  ?  2.  In  what  way  may  we  get  an  idea  of  the 
throat  ?  3.  What  parts  of  the  throat  can  we  see  upon  looking  into  a 
friend's  mouth  ?  4.  What  is  the  pharynx?  5.  Give  some  hints  about 
the  care  of  the  throat.  6.  Describe  the  larynx.  7.  What  is  meant 
by  "Adam's  apple"?  8.  Describe  the  vocal  cords.  9.  How  is  the 
voice  produced?  10.  Upon  what  does  the  quality  of  the  voice 
depend?  11.  What  is  the  effect  of  tobacco  upon  the  throat  and  the 
lungs  ?  12.  How  does  cigarette  smoking  affect  the  throat  passages 
and  the  voice  ?  13.  What  is  the  effect  of  strong  drink  and  tobacco 
upon  the  voice? 


CHAPTER  XIII 
FIRST  AID  IN  ACCIDENTS  AND  EMERGENCIES 

384.  Frequent  Opportunities  to  give  First  Aid.  We  have 
tried  in  the  preceding  chapters  to  understand  a  few  of  the 
laws  of  health  and  to  apply  them  intelligently  to  our  daily 
living.  It  will  help  us  to  clinch  what  we  have  already 
mastered,  if  we  now  supplement  our  work  with  a  knowl- 
edge of  simple  methods  of  procedure  in  case  of  the  more 
common  and  less  serious  accidents  and  emergencies. 

Emergencies  and  accidents  are  of  frequent  occurrence. 
A  playmate  may  cut  his  leg  or  foot  with  a  scythe  or  knife, 
or  fall  and  break  his  arm.  A  child  may  accidentally  swal- 
low some  laudanum,  set  his  own  clothing  on  fire,  or  push 
a  bean  into  his  nose  or  ear.  A  teamster  may  be  brought 
in  with  his  ears  frost-bitten.  A  small  boy  may  fall  into  the 
river  and  be  brought  out  apparently  drowned.  Some  one 
of  our  own  family  may  be  taken  suddenly  sick  with  some 
contagious  disease  or  may  be  suffocated  with  coal  gas. 

All  these  and  many  other  things  of  a  like  nature  call 
for  a  cool  head,  a  steady  hand,  and  some  practical  knowl- 
edge of  what  is  to  be  done  until  medical  or  surgical  help 
is  obtained.  A  fairly  good  working  knowledge  of  such 
matters  may  be  easily  mastered. 

A  boy  or  girl  who  has  acquired  this  knowledge  and  who 
is  able  to  maintain  a  certain  amount  of  self-control  will  find 
many  opportunities  in  after  years  to  lend  a  hand  in  the 
midst  of  accidents  and  sudden  sickness. 

280 


ACCIDENTS   AND   EMERGENCIES 


281 


ACCIDENTS    AND    EMERGENCIES 


385.  What  to  do  First.  All  that  is  expected  of  us  is  to 
tide  over  matters  until  the  doctor  comes.  Retain  as  far  as 
possible  presence  of  mind,  or,  in  other  words,  keep  cool. 
Act  promptly  and  quietly,  but  not  with  haste. 


FIG.  177.     An  Accident. 

This  striking  picture,  by  a  celebrated  French  artist,  has  excited  marked  attention 
ever  since  it  was  first  exhibited  at  the  Paris  Salon.  The  grouping  is  admi- 
rable, and  by  the  absence  of  all  accessories  the  interest  is  skillfully  concen- 
trated on  the  principal  personage,  the  attending  surgeon,  and  the  pale  boy 
whose  arm  he  is  bandaging  and  who  is  striving  not  to  wince  beneath  the 
treatment.  That  the  hurt  is  not  trifling  is  shown  by  the  basin  of  blood 
and  the  look  of  concern  in  the  countenances  of  the  surrounding  family,  who 
are  yet  sufficiently  composed  to  indicate  that  there  is  no  imminent  danger. 
The  strongly  lined  faces  of  the  peasants,  with  their  varying  expressions, 
contrasted  with  the  rude  interior,  form  a  graphic  study. 

The  picture  is  used  by  the  kind  permission  of  William  Wood  &  Co.,  publishers. 


282  OUR   BODIES   AND   HOW   WE   LIVE 

Make  the  sufferer  comfortable  by  giving  him  an  abun- 
dance of  fresh  air  and  placing  him  in  a  restful  position. 
Loosen  all  tight  articles  of  clothing,  as  belts,  bindings, 
corsets,  and  collars.  Be  sure  to  send  for  a  doctor  at  once 
if  the  emergency  calls  for  any  such  skilled  service. 

386.  What  to  do  for  a  Fainting  Person.    A  fainting  person 
should  be  laid  flat  on  his  back  with  his  head  lower  than  his 
feet.     Loosen  tight  clothing.     Give  plenty  of  fresh  air  and 
sprinkle  cold  water  on  the  head  and  neck.      Smelling  salts 
may  be  held  to  the  nose  to  excite  the  nerves  of  sensation 
and  thus  stimulate  respiration. 

When  the  patient  does- not  become  conscious  in  a  few 
minutes  a  physician  should  be  called  without  delay.  Re- 
member that  in  all  cases  of  fainting  treatment  should  be 
given  promptly. 

Experiment  83.  To  show  proper  treatment  for  fainting.  Select 
several  places  about  the  schoolroom,  and  show  exactly  how  a  person 
should  be  placed,  supposing  he  has  fainted  in  a  crowded  room. 

387.  Epileptic  Fits.     Nothing  can  be  done  to  stop  epilep- 
tic fits.     Give  plenty  of  fresh  air.     Unfasten  the  clothes, 
especially  about  the  neck  and  chest.     Crowd  a  pad  made 
from  a  folded  handkerchief  or  towel  between  the  teeth  to 
prevent  the  patient  from   biting  his  lips  or  tongue.      Do 
not  try  to  make  the  sufferer  swallow  any  drink.     See  to 
it  that  he  .does  not   injure  himself   by  falling  against   a 
hard  surface. 

388.  Hysterics.     Attacks  of  hysterics  vary  in  extent  from 
an  uncontrollable  fit  of  laughing  or  crying  to  convulsions 
not  unlike  those  of  an  epileptic  character.     No  treatment 
is    really   necessary,   as   the   patient   will  usually  recover 
promptly  if  left  alone.      Sympathy  is  almost  sure  to  make 


ACCIDENTS   AND   EMERGENCIES  283 

bad  matters  worse.     A  dash  of  cold  water  in  the  face  will 
sometimes  assist  recovery. 

389.  Sunstroke  and  Heat  Exhaustion.    The  main  thing 
in  sunstroke  is  to  lower  the  temperature.     Strip  off  the  cloth- 
ing.   Apply  chopped  ice,  wrapped  in  flannel,  to  the  head. 
Rub  ice  over  the  chest  and  place  pieces  under  the  armpits 
and  at  the  sides.     If  there  is  no  ice,  apply  an  abundance 
of  cold  water  to  the  head  and  neck.     Sheets  or  cloths  wet 
with  cold  water  may  be  used. 

If  the  skin  is  cold,  moist,  or  clammy,  and  the  pulse  weak, 
the  trouble  may  be  due  to  heat  exhaustion.  Give  plenty  of 
fresh  air,  but  apply  no  cold  to  the  body.  Rest  in  bed  is 
necessary.  Apply  heat  and  give  hot  drinks. 

390.  Clothing  on  Fire.    Throw  the  person  down  on  the 
ground  or  floor,  as  then  the  flames  will  not  tend  to  rise 
toward  the  mouth  and  nostrils.    Without  a  moment's  delay 
roll  the  patient  in  a  carpet  or  rug  so  as  to  stifle  the  flames, 
leaving  only  the  head  out  for  breathing.     If  no  carpet  or 
rug  can  be  had,  use  a  coat  or  cloak. 

391.  Burns  and  Scalds.     Remove  the  clothing  in  cases  of 
scalds  and  burns  with  the  greatest  care.      Do  not  pull  off 
the  clothes  from  the  burned  places,  but  gently  loosen  them 
or  cut  them  away  bit  by  bit  with  a  pair  of  sharp  scissors. 
Save  the  skin  unbroken    if  possible,  taking  care   not  to 
break  the  blisters.     The  aim  is  to  prevent  friction,  to  keep 
out  the  air,  and  to  relieve  pain. 

In  burns  caused  by  acids  bathe  the  parts  gently  with 
an  alkaline  fluid,  as  diluted  ammonia  or  strong  soda  in 
solution,  and  afterwards  dress  the  burn. 

In  burns  caused  by  alkalies,  as  lime  and  caustic  potash, 
apply  acids,  such  as  lemon  juice  or  vinegar  diluted  with 
water. 


284 


OUR   BODIES   AND   HOW  WE   LIVE 


If  the  burn  is  slight,  put  on  strips  of  soft  linen  soaked 
in  a  strong  solution  of  baking  soda  and  water,  one  heaping 
tablespoonful  to  a  cupful  of  water.  This  is  especially  good 
for  scalds.  If  carbolized  or  even  plain  vaseline  is  at  hand, 
spread  it  freely  on  strips  of  old  linen  and  cover  well  the 
burnt  parts,  keeping  out  the  air  with  other  strips  carefully 

laid  on. 

Burns  and  scalds 
are  dangerous  in 
proportion  to  their 
extent  and  depth. 
A  deep  or  exten- 
sive burn  or  scald 
should  always  have 
prompt  medical 
attendance. 

A  mixture  made 
by  shaking  together 
until  creamy  equal 
parts  of  linseed  oil 
and  limewater,  and 
commonly  known 
as  Carron  oil,  is  one 
of  the  best  local 


FIG.  178.     Improvised  Hand  Seats:  the 
Three-Handed  Seat. 


The  useful  three-handed  seat  is  made  by  one  bearer 
grasping   the  free  wrist  of  the  other  bearer  and 
placing  his  free  hand  on  his  partner's  shoulder,  in     applications    for 
order  to  support  the  patient's  back.  . 

burns.    Soak  strips 

of  old  linen  or  absorbent  cotton  in  this  time-honored  remedy 
and  gently  apply  to  the  burnt  parts,  taking  care  to  use 
more  of  the  mixture  as  the  strips  become  dry. 

Experiment  84.  Have  a  small  quantity  of  soda,  linseed  oil,  and 
limewater  in  the  schoolroom.  Imagine  a  pupil  has  burned  his  arm 
or  hand.  Show  exactly  what  is  to  be  done  and  how. 


ACCIDENTS  AND   EMERGENCIES 


285 


392.  Frostbites.     Rub  the  frozen  parts  vigorously  with 
snow  or  snow  water  in  a  cold  room.     Continue  this  until 
a  burning,  tingling  pain  is  felt,  when  all  active  treatment 
should  cease.    Pain 

shows  that  warmth 
and  circulation  are 
beginning  to  re- 
turn. No  warm  air, 
warm  water,  or  fire 
should  be  allowed 
near  the  frozen  or 
frost-bitten  parts 
until  the  natural 
temperature  is 
nearly  restored. 

393.  Dog  Bites. 
There  is  not  much 
more  danger  from 
the  bite  of  a  dog 
that  is  not  "  mad," 
that  is,  not  suffer- 
ing  from  the  dis- 
ease called   rabies, 
than  there  is  from 
any  other  lacerated 
wound.     As  a  rule, 
the  bites  of  ani- 
mals, such  as  cats 
and  rats,  are  pain- 
ful and  liable  to  be 

poisonous.     A  bite  from  a  dog  that  is  really  "mad"  is  a  rare 
accident,  which  demands  prompt  and  fearless  treatment. 


FIG.  179.  Showing  how  the  Improvised  Three- 
Handed  Seat  may  be  used  to  carry  an  Injured 
Person  (Sec.  405). 

The  picture  also  shows  how  a  boy's  broken  leg  may  be 
treated  with  an  improvised  apparatus  made  of  two 
pieces  of  oak  bark  for  splints,  padded  with  grass  and 
held  in  place  by  two  pocket  handkerchiefs. 


286  OUR   BODIES   AND   HOW  WE   LIVE 

A  mad-dog  bite  is  really  a  lacerated  wound.  In  the  little 
roughnesses,  and  between  the  shreds,  may  be  poisonous 
saliva.  If  these  projections  and  depressions  affording  the 
lodgment  can  be  removed,  the  poison  may  not  do  much 
harm.  If  done  with  a  knife,  the  wound  would  be  converted, 
practically,  into  a  cut  wound,  and  would  require  treatment 
for  such.1 

Remove  the  clothing  at  once  from  the  bitten  part,  and 
apply  a  temporary  ligature  above  the  wound.  This  inter- 
rupts the  activity  of  the  circulation  of  the  part,  and  to  that 
extent  may  delay,  or  even  prevent,  the  absorption  of  the 
poisonous  saliva. 

If  the  wound  is  at  once  well  cleansed  with  antiseptic 
washes,  and  a  stick  of  solid  nitrate  of  silver  (lunar  caustic) 
rapidly  applied  to  the  entire  surface,  the  danger  of  blood 
poisoning  is  greatly  diminished. 

Poultices,  kept  hot  and  moist  with  antiseptic  solutions, 
may  be  applied  to  the  injured  parts  to  hasten 'the  slough- 
ing away  of  the  tissues  whose  vitality  has  been  intentionally 
destroyed. 

If  a  physician  is  at  hand,  he  will  probably  cut  out  the 
injured  portion,  or  cauterize  it  thoroughly.  A  doctor's 
help  is  not  always  at  our  command.  In  such  a  case  it 
would  be  a  safe,  and  by  no  means  a  painful,  procedure  to 
take  a  poker,  or  other  suitable  piece  of  iron,  heat  it  red  hot, 
and  cauterize  the  entire  surface  of  the  wound. 

1  Any  dog,  after  having  bit  a  person,  is  apt,  under  a  mistaken  belief,  to 
be  at  once  killed.  This  should  not  be  done.  The  suspected  animal  should 
be  immediately  placed  in  confinement  and  watched,  under  proper  safe- 
guards, for  the  appearance  of  any  symptoms  that  indicate  rabies.  Should 
no  pronounced  symptoms  indicate  this  disease  in  the  dog,  a  great  deal  of 
unnecessary  mental  distress  and  worry  can  be  saved  both  the  person  bitten 
and  his  friends. 


ACCIDENTS   AND   EMERGENCIES  287 

394.  Stings  by  Venomous  Insects,  as  Bees  and  Wasps. 

Remove  the  sting  if  it  can  be  seen.  Vinegar  and  water, 
dilute  ammonia,  alcohol,  or  cologne  water  will  give  much 
relief.  Moist  earth  or  cold  water  if  applied  at  once  will 
afford  some  relief. 

In  stings  from  plants,  nettles,  etc.,  great  relief  will  be 
given  by  the  prompt  application  of  a  dilute  solution  of 
ammonia  or  of  baking  soda. 

395.  Bleeding  from  the  Nose.    Let  the  patient  sit  upright. 
Raise  the  arm  on  the  bleeding  side  above  the  head.    Do  not 
blow  the  nose.    Wring  out  two  towels  in  cold  water ;  wrap 
one  around  the  neck  and  the  other  properly  folded  over 
the  forehead  and  upper  part  of  the  nose.     In  severe  cases, 
put  the  feet  in  water  as  warm  as  can  be  borne.     Plug  the 
nostril  with  a  piece  of  absorbent  cotton  which  has  been 
wet  with  strong  borax  or  alum  water. 

When  the  nostril  has  been  plugged,  especially  if  the 
patient  is  a  young  child,  it  is  important  to  make  sure  that 
blood  is  not  trickling  down  into  the  throat  from  the  back 
of  the  nose. 

396.  Foreign  Bodies  in  the  Nose.    Young  children  are  apt 
to  push  beans,  peas,  fruit  stones,  buttons,  and  other  small 
objects  into  their  own  nose  or  that  of  some  playmate.    The 
child  may  usually  be  made  to  expel  the  object  by  blowing 
the  nose  hard  while  the  clear  side  is  closed  by  pressure 
with  the  fingers.     At  other  times  a  sharp  blow  between 
the  shoulders  will  cause  the  body  to  fall  out.     A  hairpin, 
which  has  been  first   straightened  and  then  bent  into  a 
small  hook  at  one  end,  may  be  gently  used  to  remove 
foreign  objects  from  the  ear  and  the  nose. 

397.  Foreign  Bodies  in  the  Throat.    Bits  of  food  or  other 
small  objects  sometimes  lodge  in  the  throat,  and  are  easily 


288  OUR   BODIES  AND   HOW  WE   LIVE 

extracted  by  the  forefinger,  or  they  may  be  forced  out  of 
the  passages  by  prompt  and  vigorous  slaps  on  the  back. 

If  the  object  has  actually  passed  into  the  windpipe,  caus- 
ing sudden  fits  of  spasmodic  coughing,  with  a  dusky  hue 
of  the  face  and  fingers,  surgical  help  must  be  called  with- 
out delay. 

If  small  objects,  like  coins,  pencils,  keys,  nails,  buttons, 
etc.,  are  swallowed,  it  is  not  necessary  to  take  physic. 
Hard-boiled  eggs,  cheese,  and  potatoes  should  be  freely 
eaten,  so  that  the  intruding  substance  may  be  infolded  in 
a  mass  of  solid  food  and  carried  safely  through  the  bowels. 

The  back  of  the  throat  should  be  examined  in  a  strong 
light,  for  the  body  may  be  arrested  at  the  entrance  to  the 
gullet,  and,  if  seen,  can  often  be  dislodged  by  the  fingers  or 
some  improvised  instrument. 

398.  Foreign  Bodies  in  the  Ear.    Children  sometimes  push 
into  the  ear  such  small  articles  as  grains  of  corn,  buttons, 
pebbles,  or  beans.     Syringe  in  a  little  warm  water,  which 
will  often  wash  out  any  substance  which  is  not  likely  to 
swell.     If  the  substance,  however,  is  likely  to  swell,  do  not 
syringe  the  ear,  but  try  to  remove  the  foreign  body  by 
gently  extracting  it  with  some  homemade  apparatus. 

If  live  insects  get  into  the  ear,  drop  in  a  little  sweet  oil, 
glycerin,  melted  vaseline,  or  warm  sirup.  If  the  tip  of  the 
ear  is  pulled  up  gently,  the  liquid  will  flow  in  more  readily. 
If  a  light  is  held  close  to  the  outside  of  the  ear,  the  insect 
may  be  coaxed  to  crawl  out,  being  attracted  by  the  bright 
flame. 

399.  Foreign  Bodies  in  the  Eye.     Cinders,   particles    of 
dust,  bits  of  metal,  and  other  small  bodies  may  get  into  the 
eye  and  cause  much  pain.     Never  rub  the  eye.     Hold  the 
lid  away  from  the  eyeball  and  the  tears  will  usually  wash 


ACCIDENTS   AND   EMERGENCIES 


289 


the  substance  away.     Dash  water  with  the  hand  into  the 
eye  when  the  lids  are  gently  pulled  apart. 

Sometimes  the  upper  lid  must  be  turned  back.  This 
is  usually  done  as  follows.  Seize  the  lashes  between  the 
thumb  and  forefinger  and  draw  the  edge  of  the  lid  away 
from  the  eyeball.  Now,  telling  the  patient  to  look  down, 
press  a  slender  lead 
pencil  or  penholder 
against  the  lid,  parallel 
to  and  above  the  edge, 
and  then  pull  the  edge 
up  and  turn  it  over  the 
pencil  by  means  of  the 
lashes. 

The  eye  is  now  ex- 
amined readily,  and  usu- 
ally the  foreign  body 
may  be  seen  and  easily  removed  with  the  corner  of  a  pocket 
handkerchief.  After  the  substance  has  been  removed,  bathe 
the  eye  for  some  time  with  hot  water  to  soothe  the  local 
irritation.  This  irritation  often  gives  rise  to  the  feeling  that 
the  foreign  substance  still  remains  in  the  eye. 

400.  Contusions  and  Bruises.  An  injury  to  the  soft  tis- 
sues, caused  by  a  blow,  squeeze,  or  pinch  from  some  instru- 
ment, or  by  a  fall,  is  a  contusion  or  bruise.  A  black  eye,  black 
and  blue  spots,  an  injury  caused  by  a  fall  from  a  bicycle,  and 
a  finger  hurt  by  a  baseball  are  familiar  examples  of  injuries 
which  ordinarily  require  simple  treatment. 

Wring  out  old  towels  or  pieces  of  flannel  in  hot  water 
and  apply  to  the  parts,  changing  as  they  become  cool. 
For  cold  applications,  cloths  wet  with  equal  parts  of  water 
and  vinegar,  or  witch-hazel  may  be  used. 


FIG.  i  So. 

Showing  how  the  upper  eyelid  may  be  everted 
with  a  pencil  or  penholder. 


290  OUR  BODIES    AND    HOW  WE   LIVE 

When  wounds  are  made  with  ragged  edges,  such  as 
broken  glass  and  splinters,  more  skill  is  called  for.  Remove 
every  bit  of  the  foreign  substance.  If  the  skin  about  the 
wound  seems  to  need  washing,  it  should  be  done  with  an 
antiseptic  solution.  Bring  the  torn  edges  together  and  hold 
them  in  place  with  strips  of  plaster. 

Wounds  made  by  rusty  nails  and  tools,  if  neglected, 
often  lead  to  serious  results  from  blood  poisoning.  Keep 
such  wounds  clean  by  washing  or  syringing  them  twice 
a  day  with  antiseptics  which  kill  the  bacteria  or  prevent 
their  growth. 

Deaths  following  injuries  from  toy  pistols  and  percussion 
caps  have  become  so  frequent  in  recent  years  that  it  is  not 
safe  to  depend  upon  home  treatment  for  such  accidents. 
All  such  wounds  should  be  treated  at 
once  by  skilled  physicians. 

JTIG   jgj  Experiment  85.     To  show  the  proper  way 

of  treating  cuts  and  bruises.     Let  red-pencil 
Showing  how  a  square  knot     markg   made  Qn  tfa     f  fi 

may  be  tied  with  a  hand- 
kerchief (Exp.  87).  stand  for  cuts.    Apply  suitable  strips  of  plaster 
in  a  proper  way  for  a  variety  of  imaginary  cuts. 

After  putting  on  the  plaster,  practice  bandaging  the  parts  with  strips 
of  cotton  cloth  rolled  for  the  purpose.  Practice  using  the  handker- 
chief for  a  variety  of  bandages. 

401.  Injuries  to  the  Blood  Vessels.  It  is  very  important 
to  know  the  difference  between  the  bleeding  from  an  artery 
and  that  from  a  vein.  If  an  artery  bleeds,  the  blood  leaps  in 
spurts  and  is  of  a  scarlet  color.  If  a  vein  bleeds,  the  blood 
oozes  in  a  steady  stream  and  is  of  a  somewhat  darker  color. 

Bleeding  from  an  artery  is  dangerous  in  proportion  to 
the  size  of  the  vessel,  and  as  a  result  life  itself  may  be 
speedily  lost.  In  arterial  bleeding,  always  remember  to  make 
deep  pressure  between  the  wound  and  the  heart. 


ACCIDENTS   AND    EMERGENCIES 


29I 


402.  What  to  do  First.     Do  not  be  afraid  to  act  at  once. 
A  resolute  grip  in  the  right  place  with  firm  fingers  will  do 
well  enough  until  a  knotted  handkerchief,  stout  cord,  shoe 
string,  or  an  improvised 

tourniquet l  is  ready  to 
take  its  place.  If  the 
flow  of  blood  does  not 
stop,  change  the  pres- 
sure until  the  right  spot 
is  found. 

403.  Where  and  how 
to  apply  Pressure.    The 
principal  places  in  which 
to  apply  pressure  when 
arteries  are  injured  and 
bleeding  should   always 
be  kept  in  mind. 

If  in  the  finger,  grasp 
it  with  the  thumb  and 
forefinger  and  pinch  it 
firmly  on  each  side ;  if 
in  the  hand,  press  on  the 


1  A  tourniquet  is  a  bandage, 
handkerchief,  or  strap  of  web- 
bing into  the  middle  of  which 
a  stone,  a  potato,  a  small  block 
of  wood,  or  any  hard,  smooth 
body  is  tied.  The  band  is  tied 
loosely  about  the  limb,  the  hard 


FIG.  182. 

Showing  how  an  improvised  apparatus,  or  tem- 
porary tourniquet,  may  be  adapted  to  arrest 
bleeding  from  an  artery  in  the  arm.  This 
apparatus  consists  of  half  of  a  potato  held 
in  place  over  the  artery  by  a  pocket  hand- 
kerchief used  as  a  band.  A  stick,  picked  up 
on  the  ground,  is  inserted  beneath  the  band 
on  the  opposite  side  of  the  limb  and  used  as 
a  lever  to  press  the  potato  firmly  against 
the  artery. 


body  is  held  over  the  artery  to 
be  constricted,  and  a  stick  is  inserted  beneath  the  band  on  the  opposite 
side  of  the  limb  and  used  to  twist  the  band  in  such  a  way  that  the 
limb  is  tightly  constricted  thereby,  and  the  hard  body  thus  made  to 
compress  the  artery. 


292  OUR  BODIES  AND   HOW  WE   LIVE 

bleeding  spot,  or  grasp  firmly  with  the  ringers  just  above 

and  on  both  sides  of  the  wrist. 

For  injuries  below  the  elbow,  grasp  the  upper  j>art  of  the 

arm  with  the  hands  and  squeeze  hard.     The  main  artery 

runs  in  the  middle  line  of  the  bend  of  the  elbow.     Tie  a 

knotted  handkerchief  or  cord 
here  and  bend  the  forearm  so 
as  to  press  hard  against  the 
knot. 

For  the  upper  arm,  press 
with  the  fingers  against  the 
bone  on  the  inner  side  and 
just  on  the  edge  of  the  bulg- 
ing part  of  the  biceps  muscle. 
Take  a  stout  stick  of  wood 
about  a  foot  long  and  twist 
the  cord  hard  with  it,  bring- 
ing the  knot  firmly  over  the 
artery  (Fig.  190). 

For  the  foot  or  leg,  use 
pressure,  as  before,  in  the 
hollow  behind  the  knee  just 

Showing  how  firm  pressure  may  be  made  ,               ,,              ir       r     j.i 

with  the  fingers  to  compress  the  brach-  above     the     Calf     of     the     leg. 

ial  artery  of  the  left  arm.    Some  large  Bend    the    thigh    towards    the 

superficial  veins  are  also  shown.  i  i     •          11 

abdomen  and  bring  the  leg  up 
against  the  thigh,  with  the  knot  in  the  bend  of  the  knee. 

Experiment  86.  To  stop  bleeding  from  the  arteries.  Locate  the 
principal  arteries  on  your  own  person  and  that  of  a  friend.  Let  red- 
crayon  or  red-pencil  marks  stand  for  the  course  of  the  arteries. 

Now,  with  strings,  cords,  shoe  strings,  handkerchiefs,  or  strips  of 
clothing,  practice  tying  them  so  as  to  press  deeply  and  firmly  in  the 
proper  place.  Let  each  one  in  the  class  practice  on  the  same  artery. 
Criticise  and  improve  one  another's  work. 


ACCIDENTS   AND   EMERGENCIES  293 

404.  Bleeding  from  the  Lungs.    Blood  that  comes  from 
the  lungs  is  bright  red  and  frothy.     There  is  rarely  much 
blood ;  it  usually  follows  coughing,  feels  warm,  and  has  a 
salty  taste. 

Bleeding  from  the  lungs,  or  pulmonary  hemorrhage, 
is  a  grave  symptom.  A  doctor  should  be  called  at  once. 
The  patient  should  be  made  to  lie  down  with  the  head  and 
shoulders  slightly  raised.  Perfect  rest  and  quiet  must  be 
insisted  upon.  Finely  chopped  ice  may  be  eaten  to  relieve 
thirst.  Loosen  the  clothing,  keeping  the 
shoulders  well  raised  and  the  body  in  a 
reclining  position. 

Experiment  87.    How  to  tie  a  square  knot. 
With   a   handkerchief,   a   shoe   string,   a   roller  „ 

i          j  j         r  •  j.-         j.    •  -TIG.  154- 

bandage,  or  cords  of  various  sizes,  practice  tying 

a  square  knot  until  it  can  be  done  accurately    ShowinS how  a  S(luare 

knot    may   be    tied 
and  rapidly.  with  a  cord 

A  square  knot l  is  tied  by  holding  an  end  of  a 

bandage  or  cord  in  each  hand,  and  then  passing  the  end  in  the  right 
hand  over  the  one  in  the  left  and  tying;  the  end  now  in  the  left  hand 
is  passed  over  the  one  in  the  right  and  again  tied  (Fig.  181). 

405.  Broken  Bones.    Parts  of  the  body  which  have  sus- 
tained a  break  or  fracture  of  one  or  more  bones  should  be 
handled  with  great  care  and  tenderness.     The  most  impor- 
tant signs  of  a  broken  bone  are  the  fact  of  an  accident 
having  occurred  of  sufficient  severity  to  break  the  bone, 
pain  at  a  certain  fixed  point,  the  inability  to  bend  the  limb 
or  move  the  bone  in  a  natural  position,  and  the  grating 

1  If  the  student  would  render  efficient  help  in  accidents  and  emergencies, 
to  say  nothing  of  service  on  many  other  occasions,  he  must  learn  how  to 
tie  a  square,  or  "  reef,"  knot.  This  knot  is  secure  and  does  not  slip,  as  does 
the  "  granny "  knot.  The  square  knot  is  the  one  used  by  surgeons  in 
ligating  vessels  and  securing  bandages.  Unless  one  knows  the  difference, 
the  insecure  "  granny  "  knot  may  be  substituted. 


294 


OUR   BODIES   AND    HOW   WE   LIVE 


sensation  which  may  be  felt  or  heard  at  the  point  of  injury. 
Never  move  the  injured  person  until  the  limb  is  made 
safe  from  further  injuries  by  putting  on  temporary  splints. 
If  you  do  not  need  to  move  the  person,  keep  the  limb  per- 
fectly quiet  and  in  a  natural,  comfortable  position  until  the 

doctor  comes.  If  the 
accident  happens  in  the 
woods,  the  limb  should 
be  bound  with  handker- 
chiefs or  strips  of  cloth- 
ing to  a  piece  of  board, 
pasteboard,  or  bark, 
padded  with  moss  or 
grass,  which  will  do  well 
enough  for  a  temporary 
splint  (Fig.  179). 

Send  for  a  doctor  at 
once  to  set  the  broken 
bone  (Figs.  30-32). 

Experiment  88.  To  carry 
an  injured  person.  Take 
some  one  of  the  small  boys 
and  show  how  he  should 
be  carried  in  a  three-handed 
seat  in  case  of  injury. 


FIG.  185. 

Showing  how  an  improvised  apparatus  may  be 
used  for  a  broken  radius.  This  temporary 
dressing  consists  of  two  pieces  of  oak  bark 
for  splints,  with  grass  for  padding,  and 
is  secured  in  place  by  a  boy's  long  stock- 
ing and  a  pocket  handkerchief. 


406.   Sprains.     The 

wrenching  or  tearing  of 
the  ligaments  about  a 
joint  is  called  a  sprain.  Sprains  are  often  acquired  in  the 
course  of  outdoor  sports.  Thus,  sprains  of  the  fingers  are 
common  enough  with  baseball  players.  There  is  at  once 
pain  on  movement  and  swelling. 


ACCIDENTS   AND    EMERGENCIES  295 

Keep  the  injured  parts  at  rest  and  soak  them  in  water 
as  hot  as  can  be  borne.  Continue  the  treatment  for  several 
hours  if  necessary,  until  the  pain  and  swelling  have  been 
reduced.  Cold  wa-ter  is  often  used,  but  hot  water  is  better. 
If  prompt  relief  is  not  afforded,  secure  the  services  of  a 
doctor.  A  crippled  or  weak  joint  may  result  from  lack  of 
prompt  and  proper  treatment  of  a  sprain. 

407.  Asphyxia,  or  Suffocation.  The  chief  dangers  from 
poisoning  by  noxious  gases  come  from  the  fumes  of  burn- 
ing coal  in  the  furnace,  stove,  or  range ;  from  blowing 


FIG.  186. 

Showing  how  a  pillow,  an  inside  coat,  a  "  sweater,"  or  a  blanket  may  be 
used  as  a  temporary  splint  on  a  broken  leg. 

out  gas  or  turning  it  down  and  having  it  blown  out  by  a 
draught ;  from  the  foul  air  often  found  in  old  wells  or 
mines;  and  from  the  fumes  of  burning  charcoal. 

The  first  and  essential  thing  to  do  is  to  give  fresh  air. 
Remove  the  pe-rson  to  the  open  air  and  place  him  on  his 
back.  Remove  tight  clothing  about  the  throat  and  waist, 
and  dash  cold  water  on  the  face  and  chest.  As  soon  as  the 
patient  can  swallow,  give  hot  coffee  or  hot  ginger  tea. 

Friction  applied  to  the  limbs  should  be  kept  up.  If 
breathing  has  ceased  or  is  very  feeble,  artificial  respiration 
must  be  begun  at 'once  and  the  doctor  sent  for  (Sec.  409). 


296 


OUR   BODIES   AND   HOW  WE   LIVE 


408.  What  to  do  in  Apparent  Drowning.  Remove  all 
tight  clothing  from  the  neck,  chest,  and  waist.  Sweep  the 
forefinger,  covered  with  a  handkerchief  or  towel,  round  the 
mouth  to  free  it  from  froth  and  mucus.  Turn  the  body 
on  the  face,  raising  it  a  little  with  the  hands  under  the 
hips  to  allow  any  water  to  run  out  from  the  air  passages. 
Take  only  a  moment  for  this. 

Lay  the  person  flat  upon  the  back,  with  a  folded  coat 
or  pad  of  any  kind  to  keep  the  shoulders  raised  a  little. 
Remove  the  wet,  clinging  clothing  as  soon  as  possible.  If 


FlG.  187.     Production  of  Artificial  Respiration. 
First  movement  —  inspiration. 

in  a  room  or  sheltered  place,  strip  the  body  and  wrap  it  in 
blankets,  overcoats,  etc.  If  possible,  use  bottles  of  hot 
water,  hot  flatirons,  or  bags  of  hot  sand  round  the  limbs 


ACCIDENTS  AND   EMERGENCIES 


297 


and  feet.  Watch  the  tongue  ;  it  generally  tends  to  slip 
back  and  to  shut  off  the  air  from  the  glottis.  Wrap  a 
coarse  towel  round  the  tip  of  the  tongue  and  keep  it  well 


FIG.  1 88.     Production  of  Artificial  Respiration. 
Second  movement  —  expiration. 

pulled  forward.  The  first  sign  of  recovery  is  often  seen 
in  the  slight  pinkish  tinge  of  the  lips  or  finger  nails.  That 
the  pulse  cannot  be  felt  at  the  wrist  is  of  little  value  in 
itself  as  a  sign  of  death.  Life  may  be  present  when  only 
the  most  experienced  ear  can  detect  the  heart  beat. 

When  a  person  can  breathe  even  a  little  he  can  swallow. 
Give  a  few  teaspoonfuls  at  a  time  of  hot  black  coffee  or 
hot  ginger  tea.  Hold  smelling  salts  or  hartshorn  to  the 
nose.  Meanwhile  do  not  fail  to  keep  up  artificial  warmth 
in  the  most  vigorous  manner. 


OUR   BODIES   AND   HOW  WE   LIVE 

409.  How  to  produce  Artificial  Respiration.  The  main 
thing  to  do  in  apparent  drowning,  or  in  other  cases  of  sus- 
pended animation,  is  to  produce  artificial  respiration  until  the 
natural  breathing  comes  or  all  hope  is  lost.  This  is  the 
simplest  way  to  do  it.  The  person  lies  on  the  back.  Let 
some  one  kneel  behind  the  head.  Grasp  both  arms  near 
the  elbows  and  sweep  them  upward  above  the  head  until 
they  nearly  touch.  Make  a  firm  pull  for  a  moment.  This 
tends  to  fill  the  lungs  with  air  by  drawing  the  ribs  up  and 
making  the  chest  cavity  larger.  Now  return  the  arms  to 
the  sides  of  the  body  until  they  press  hard  against  the  ribs. 
This  tends  to  force  out  the  air  and  makes  a  complete  act  of 
artificial  respiration.  Repeat  this  act  about  fifteen  times 
every  minute  for  several  hours  if  necessary. 

Experiment  89.  To  illustrate  proper  treatment  for  apparent 
drowning.  Show  exactly  how  artificial  respiration  is  done.  Let  a 
boy  lie  on  the  floor  or  settee,  and  illustrate  the  process  in  every  detail. 
It  would  be  an  excellent  idea  for  a  teacher  to  meet  his  boys  at  their 
bathing  place,  or  even  on  the  playground,  and  instruct  them  more 
freely  concerning  every  step  in  the  treatment. 

Let  two  boys  go  through  the  process  on  a  playmate  under  the  eye 
of  the  teacher ;  then  others  may  follow  their  example. 


POISONS    AND    THEIR    ANTIDOTES 

410.  Careless  Use  of  Poisons.  Poisons  of  various  kinds 
are  quite  generally  used  in  the  trades  and  kept  about  the 
house  and  premises  as  medicines,  as  disinfectants  for  killing 
insects  and  rats,  and  for  many  other  purposes. 

People  are  often  careless  about  poisons  and  leave  them 
wrapped  in  a  piece  of  paper  or  in  some  unlabeled  bottle, 
or  even  in  a  cupboard  or  on  a  shelf  in  a  kitchen  closet, 


ACCIDENTS   AND    EMERGENCIES 


299 


shed,  or  stable.  Children  either  mistake  them  or  are  some- 
times urged  by  a  playmate  to  swallow  the  contents  of  some 
bottle  or  package. 

The  many  fatal  accidents  due  to  drinking  carbolic  acid 
or  aconite  by  mistake  may  serve  as  a  familiar  example  of 
how  stupid  or  careless  people  may  be. 

411.  How  to  prevent  the  Improper  Use  of  Poisons.    All 
poisons  should  always  be  put  in  bottles  carefully  labeled, 
and  the  word  POISON  should  be  plainly  printed  in  large 
letters    directly    across    the    label.  ^ 

Fasten  the  cork  firmly  to  the  bottle 
by  wire  picture  cord  or  copper  wire 
twisted  into  a  knot  at  the  top.  This 
simple  precaution  would  certainly 
prevent  a  person  from  mistaking,  in 
the  dark,  carbolic  acid,  oxalic  acid, 
etc.,  for  medicine. 

Poison  should  never  be  kept  in 
the  same  place  with  medicines  or 
other  bottled  preparations  used  in  the 
household.  Put  them  in  some  secure 
place  and  under  lock  and  key. 

Another  very  simple  rule  is  never 
to  use  the  contents  of  any  package  or 
bottle  unless  you  know  exactly  what 
it  is.  Do  not  guess  at  it  or  take  any 
chances,  but  destroy  it  at  once. 

412.  Some  Common  Emetics. 
Poisons  are  often  taken  when  medical 

help,  especially  in  the  country,  cannot  be  had  at  short  notice. 
They  often  do  their  work  rapidly.  Something  must  be 
done  to  counteract  them,  and  that  at  once  and  in  earnest. 


f 


FIG.  i! 


9.    BLACKBOARD 
SKETCH. 


The  dotted  line  shows  the 
course  of  the  right  fem- 
oral artery. 


300  OUR  BODIES  AND   HOW  WE   LIVE 

For  most  poisons,  the  stomach  should  be  emptied  as 
speedily  as  possible.  Make  a  quart  of  warm  soapsuds. 
Force  the  sufferer  to  gulp  it  down,  a  cupful  at  a  time. 
Run  the  finger  down  the  throat  and  hasten  the  vomiting. 

A  good  emetic  is  made  by  stirring  a  heaping  tablespoon- 
ful  of  ground  mustard  in  a  pint  of  warm  water.  Give 
a  cupful  every  ten  minutes  until  vomiting  is  produced. 
Common  salt  may  be  used  in  place  of  mustard.  Stir  a 
handful  of  powdered  alum  into  a  cupful  of  sirup  and  give 
a  tablespoonful  every  ten  minutes.  It  affords  a  prompt 
emetic. 

Be  in  earnest  about  it  and  do  not  waste  time  to  see  if 
the  poisoned  person  likes  such  treatment.  Vomiting  will 
not  do  any  harm.  Remember  that  the  poison  may  destroy 
life  in  a  few  minutes. 

413.  Different  Kinds  of  Poison.    For  convenience,   the 
more  common  poisons  may  be  arranged  in  different  classes. 

Some  poisons  are  acids,  like  the  oil  of  vitriol ;  others  are 
alkalies,  like  lye. 

Some  poisons  are  irritant  mineral  poisons,  like  arsenic  or 
sugar  of  lead;  while  others  are  vegetable  poisons,  like  monks- 
hood  and  wild  parsnip. 

We  can  easily  remember  the  general  plan  of  treatment 
for  each  special  class  of  the  more  common  poisons. 

414.  Acid  Poisons  and  their  Antidotes.    The  oil  of  vitriol, 
nitric  acid,  and  muriatic  acid  are  in  common  use  in  certain 
workshops    and   are  occasionally   used  in  the  household. 
These  are  caustic    mineral   acids    that  rapidly  burn  and 
destroy  the  living  tissues. 

Give  an  alkali.  Give  large  quantities  of  strong  soap- 
suds, chalk,  tooth  powder,  soda  or  saleratus  water,  mag- 
nesia, or  limewater.  Scrape  off  the  whiting  from  the  wall 


ACCIDENTS   AND   EMERGENCIES 


301 


or  dig  out  a  piece  of  plaster.  Dilute  it  with  large  quantities 
of  water  and  give  the  mixture.  Follow  this  treatment  with 
some  mild,  soothing  tea  made  of  flaxseed  or  Irish  moss. 

Oxalic  acid  is  often  mistaken  for  granulated  sugar  or  Epsom 
salts.  For  an  antidote  use  chalk,  whitewash,  plaster,  etc., 
as  before. 

Carbolic  acid  in  solution  is  very  commonly  used  about  the 
house.  It  is  a  highly  dangerous  poison  and  generally  fatal. 
Provoke  vomiting  by  giving  large 
quantities  of  soapsuds  and  sweet  oil 
mixed  together.  Follow  with  large 
draughts  of  sweet  oil  or  milk.  Large 
doses  of  Epsom  salts  may  be  used. 

415.  Alkaline  Poisons  and  their 
Antidotes.     The  common  alkalies 
taken  as  poisons  are  ammonia,  potash, 
and  soda,  usually  dissolved  but  often 
in  the  form  of  lye.     In  addition  to 
other  poisons,  horse  liniments  and 
other    liniments    generally    contain 
ammonia.    They  are  often  taken  by 
mistake.    Alkalies  burn  the  mucous 
membranes  rapidly  and  severely. 

Give  acids.  Give  vinegar  freely. 
Lemon  juice  may  be  used.  Large 
quantities  of  sweet  oil,  linseed  oil, 
and  castor  oil  may  be  given. 

416.  Metallic  Poisons  and  their  Antidotes.    Arsenic  is  a 
white,  sweetish  powder  often  used  to  kill  rats.     It  is  occa- 
sionally taken  by  mistake.     Paris  green  is  a  form  of  arsenic 
used  by  farmers.     Arsenic  is  also  found  in  ratsbane  and 
the  various  kinds  of  powder  used  to  kill  flies. 


FIG.  190.     BLACKBOARD 
SKETCH. 

The  dotted  line  shows  the 
course  of  the  left  brachial 
artery. 


302  OUR  BODIES  AND   HOW  WE   LIVE 

Provoke  vomiting  at  once.  Give  large  quantities  of  milk, 
the  whites  of  eggs,  flour  and  water,  or  oil  and  limewater. 

In  sugar  of  lead  poisoning,  provoke  vomiting  and  give 
Epsom  salts. 

In  copper  poisoning  by  blue  vitriol  and  verdigris,  use 
milk  or  white  of  eggs  followed  by  flaxseed  tea. 

Use  the  same  treatment  in  mercurial  poisoning,  occasioned 
by  drinking  solutions  of  corrosive  sublimate,  which  is  chiefly 
used  as  a  disinfectant. 

Children  sometimes  eat  the  phosphorus  from  matches. 
Use  plenty  of  magnesia,  chalk,  or  whiting,  but  no  oil.  This 
poison  acts  slowly  and  usually  there  is  time  enough  to  get 
medical  help. 

417.  The  Various  Forms  of  Opium  as  Poisons.  The  vari- 
ous forms  of  opium  are  often  taken  by  mistake  or  in  an 
overdose.  The  narcotic  effects  of  laudanum,  paregoric, 
Dover's  powder,  most  cholera  mixtures,  and  many  of  the 
so-called  "soothing  sirups"  and  "drops"  are  due  to  opium. 

Brisk  emetics  must  be  used  until  they  act  thoroughly. 
Give  plenty  of  hot,  strong  coffee  without  milk  or  sugar. 
Do  not  allow  the  patient  to  fall  into  a  deep  sleep.  Dash 
cold  water  over  the  head  and  shoulders  and  slap  the  skin 
briskly  with  wet  towels  or  with  a  slipper.  Medical* help 
must  be  called  at  once. 

NOTE.  —  The  teacher  or  student  who  is  disposed  to  study  the 
several  topics  of  this  chapter  in  more  detail  than  is  possible  in  an 
elementary  text-book  may  find  the  necessary  material  in  the  following 
books.  They  are  readily  obtained  of  booksellers  or  may  be  found 
in  the  public  libraries  of  larger  towns:  Dulles'  Accidents  and  Emer- 
gencies (price  $1.00);  Pilcher's  First  Aid  in  Illness  and  Injury 
(price  $2.00);  Doty's  Prompt  Aid  to  the  Injured  (price  $1.50),  and 
Drinkwater's  First  Aid  to  the  Injured  (Temple-Primer  Series;  price 
50  cents). 


ACCIDENTS   AND   EMERGENCIES  303 

418.  Poisonous  Plants.  There  are  certain  poisonous  plants 
occasionally  eaten  by  children  and  others  which  often  pro- 
duce serious  and  sometimes  fatal  results.  Children  are 
somewhat  disposed  to  "dare"  their  playmates  to  eat  of 
plants  which  they  find  in  their  walks. 

We  have  space  to  refer  to  only  a  few  of  the  most  com- 
mon poisonous  plants. 

Water  hemlock,  commonly  known  as  wild  parsnip,  cowbane, 
etc.,  is  poisonous. 

Aconite,  otherwise  known  as  monkshood  and  wolfsbane, 
might  be  mistaken  for  horse-radish.  It  is  a  dangerously 
poisonous  plant.  Several  species  of  lobelia  are  poisonous, 
as  the  large  lobelia  with  its  blue  blossoms,  the  cardinal  flower 
with  its  tall  spike  of  red  flowers,  and  the  well-known  Indian 
tobacco. 

Several  varieties  of  toadstools  are  poisonous  and  are  occa- 
sionally mistaken  for  edible  mushrooms.  All  parts  of  the 
poison  sumac  (poison  dogwood,  poison  elder)  are  dangerous. 

Children  should  be  taught  to  know  what  particular  fruits, 
seeds,  and  flowers  of  plants  are  poisonous. 

Most  persons  are  susceptible  even  to  the  touch  of  poison 
ivy,  all  parts  of  which,  especially  its  juice,  are  poisonous. 
A  few  other  plants,  as  poison  dogwood  and  stramonium  plant, 
are  also  poisonous  to  the  touch. 

Give  emetics  that  will  produce  prompt  and  brisk  vomit- 
ing for  poisoning  from  eating  plants.  Stimulating  drinks 
and  purgatives  are  usually  indicated. 

Inasmuch  as  most  vegetable  poisons  act  promptly  and  the 
treatment  is  difficult  in  many  cases,  the  services  of  a  phy- 
sician are  usually  needed  without  delay. 


304  OUR  BODIES   AND   HOW  WE   LIVE 


QUESTIONS  ON  THE  TEXT 

I.  How  may  we  supplement  what  we  have  learned  in  the  preceding 
chapters?     2.  What  are  some  of  the  more  common  accidents  and 
emergencies  that  may  occur  at  any  moment  ?     3.  What  are  some  of 
the  things  that  we  should  do  first  ?     4.  What  should  be  done  for  a 
fainting  person  ?   5.  Describe  the  treatment  for  epileptic  fits.    6.  What 
would  you  do  for  hysterics  ?     7.  Describe  the  treatment  for  sunstroke 
and  heat  exhaustion.     8.  Mention  some  things  to  be  done  when  the 
clothing  is  set  on  fire.     9.  Describe  the  treatment  for  burns  and 
scalds.     10.  What  may  be  done  for  frostbites  ? 

II.  Describe  in  some  detail  the  nature  and  treatment  of  dog  bites. 
12.  What  is  to  be  done  for  bleeding  from  the  nose.     13.  Describe  the 
treatment  for  foreign  bodies  in  the  nose;  in  the  throat;  in  the  ear; 
in  the  eye.     14.  Show  what  may  be  done  for  contusions  and  bruises. 
15.  How  would  you  know  the  difference  between  bleeding  from  an 
artery  and  that  from  a  vein  ?     16.  What  is  the  chief  thing  to  do  for 
arterial  bleeding  ?    17.  How  should  pressure  be  applied  to  stop  bleed- 
ing, at  the  fingers?  below  the  elbow?  on  the  upper  arm?  on  the  foot  or 
leg?    18.  What  would  you  do  for  bleeding  from  the  lungs?  19.  Describe 
in  some  detail  the  treatment  for  broken  bones.     20.  What  should  be 
done  for  sprains  ? 

21.  What  is  the  first  and  essential  thing  to  do  in  cases  of  suffo- 
cation? 22.  Describe  fully  what  to  do  for  apparent  drowning. 
23.  Describe  the  process  of  producing  artificial  respiration.  24.  How 
may  the  improper  use  of  poisons  be  prevented  ?  25.  Describe  a  few 
of  the  more  common  emetics.  26.  What  are  some  of  the  more  com- 
mon acid  poisons  and  their  antidotes  ?  27.  Name  the  alkaline  poisons 
and  their  antidotes.  28.  Mention  a  few  metallic  poisons,  giving  their 
antidotes.  29.  What  are  the  more  common  forms  of  opium?  30.  What 
should  be  done  for  opium  poisoning? 

31.  Mention  some  of  the  more  common  poisonous  plants.  32.  What 
is  the  general  treatment  in  cases  of  accidental  poisoning  from  plants? 


CHAPTER  XIV 

BACTERIA;   DISEASES  THAT  SPREAD  AND  DISINFECT- 
ANTS; CARE  OF  THE  SICK  ROOM 

419.  The  Work  done  by  Bacteria.    We  all  know  that  in 
hot  weather  milk,  meat,  and  every  kind  of  moist  food  quickly 
becomes  bad.     In  a  previous  chapter  we  learned  that  a 
glass  of  sweetened  water  or  sweet  cider,  if  left  in  a  warm 
place,   soon  begins   to  ferment   or   "work"   (Chapter  V). 
Everybody  knows  that  if  the  dead  body  of  some  animal  is 
buried  in  the  ground,  it  soon  begins  to  putrefy  and  after 
a  time  almost  entirely  disappears. 

All  these  and  countless  other  wonderful  changes  in  dead 
organic  matter,  known  as  putrefaction  or  fermentation,  are  due 
to  the  work  done  by  myriads  of  living  organisms  called 
bacteria.  The  terms  germs,  microorganisms,  and  microbes  are 
commonly  applied  to  certain  low  forms  of  plant  and  animal 
life  of  microscopic  size.  Probably  there  are  microorganisms 
that  cannot  be  seen  even  with  the  help  of  the  highest 
power  of  the  microscope. 

420.  Nature  and  Propagation  of  Bacteria.    Bacteria  are 
low  forms  of  plant  life  which  appear  as  the  tiniest  bright  rods 
or  dots  when  examined  with  a  microscope  of  great  power. 

When  bacteria  gain  an  entrance  into  fluid  suitable  for 
their  growth  they  multiply  by  division  with  incredible 
rapidity.  Thus,  in  a  cupful  of  milk  in  the  course  of  one 
hot  night  millions  upon  millions  of  bacteria  may  develop. 

305 


306 


OUR   BODIES   AND   HOW  WE   LIVE 


Under  certain  conditions  bacteria  reproduce  themselves 
by  minute  round  bodies  called  "spores"  or  eggs.  These 
spores  become  dried  without  losing  their  vitality,  and  as 
dust  may  be  carried  everywhere  by  the  winds.  Under 
favorable  conditions  they  germinate  and  become  bacteria.1 
421.  Importance  of  Bacteria  in  Nature.  Bacteria  exist 
in  the  soil  and  in  water.  They  are  wafted  as  dust  in  the 
air  all  over  the  face  of  the  earth.  We  eat  myriads  of 
them  in  our  food,  drink  them  in  water,  and  breathe  them 
in  the  dust  of  the  street,  the  house,  and  the  workshop. 
These  tiny  organisms  break  down  all  dead  organic  matter 
into  simple  chemical  substances  which  are  thus  made  more 
fit  for  the  food  of  plants.  In  other  words,  bacteria  act 
as  scavengers  which  serve  to  make  the  face  of  the  earth 
clean  and  sweet  for  all  living  things.  If  it  were  not  so, 
life  upon  the  earth  would  be  impossible.  Like  countless 
other  species  of  living  organisms,  bacteria  obey  the  relent- 

less  law  of  nature  which 
allows  only  the  fittest  to  sur- 
vive. The  rains,  the  winds, 

1  Bacteria  consist  of  many  varieties 
roughly  divided  into  groups  accord- 
ing as  they  are  spherical,  rodlike,  or 
spiral  in  shape.  The  word  "  bacillus  " 
is  commonly  applied  to  rod-shaped 
bacteria.  Each  bacterium  consists  of 
a  mass  of  protoplasm  surrounded  by 
an  ill-defined  cell  wall. 

The  bacteria  vary  considerably  in 
size.  Some  of  the  rod-shaped  varie- 
ties are  from  T^TTO to  ~5~3o~o  °f  an  mcn 
in  length  and  average  about  ^^ff 
of  an  inch  in  diameter.  It  has  been  calculated  that  a  cubic  space  of  ^  of 
an  inch  would  contain  250,000,000  of  these  minute  organisms  and  that 
they  would  not  weigh  more  than  ?fa  of  a  grain. 


FIG.  191.     Various  Forms  of 

Bacteria. 

Magnified  about  1000  diameters. 
A,  spheroidal  bacteria  in  pairs ;  B,  same 
kind  of  bacteria  in  chains ;  C,  bacteria 
found  in  pus  (grouped  in  masses  like  a 
bunch  of  grapes). 


BACTERIA 


307 


melting  snow  and  ice  scatter  them  far  and  wide  over  the 
land  and  sea  and  destroy  many  of  them. 

422.  Disease-Producing  Bacteria.    Many  kinds  of  bacteria 
are  harmless  to   our   bodies,   while   others  under  certain 

conditions  are  the  cause  of  sick- 
ness and  death.  Thus,  diphtheria, 
typhoid  fever,  consumption,  and 
probably  other  diseases  may  be 
produced  through  the  agency  of 
certain  kinds  of  bacteria. 

Surface  soils  abound  in  many 
species  of  microorganisms  which 
may  retam  their  vitality  and  viru- 
lence  for  a  long  time.  Thus,  one 
experimenter  kept  some  typhoid 
fever  bacteria  alive  in  polluted 
soil  for  four  hundred  and  fifty-six 

days.    The  disease  called  "lockjaw  "  is  known  to  be  due  to 

germs  occurring  in  the  soil  of  certain  localities  (Fig.  199). 
It  is  a  mistake  to  think  that  a  cut 

of  the  thumb  or  great  toe  is  more 

likely  to  be  followed  by  lockjaw  than 

is  a  cut  elsewhere.     The  germs  of 

lockjaw  may  enter  any  open  wound. 

423.  Bacteria  in  Food.      Food, 
both  good  and  bad,  abounds  in  bac- 

teria.    Fortunately  not  all  bacteria   FlG.  I93>  scrapings  from  the 

are    harmful   and   many    that    are      Teeth,  containing  Several 

harmful  are  destroyed  in  cooking. 

The  typhoid  fever  germ  has  been 

traced  to  ice,  ice  cream,  and  raw  oysters  that  were  fattened 

in  salt  water  polluted  with  sewage.     Bacteria  have  a  special 


FIG.  192.    A  Group  of  Soil 


Different  Kinds  of  Bacteria. 
Highly  masnified- 


308 


OUR  BODIES  AND   HOW  WE   LIVE 


fondness  for  milk  and  its  various  products,  which  are 
therefore  liable  to  be  polluted  in  many  different  ways.1 

424.  How  Bacteria  gain  Access  to  the  Body.  The  germs 
of  disease  may  gain  access  to  our  bodies  in  several  different 
ways.  Thus,  one  kind  of  bacteria  requires  a  break  in  the 
skin  in  order  to  do  harm.  This  mode  of  entrance  to  the 
body  is  called  inoculation.  This  may  result  from  using 
soiled  instruments  or  tools,  from  gunshot  injuries  made 
by  broken  glass  or  rusty  nails,  and  from  numerous  other 
causes.  Death  has  resulted  under  certain  conditions  from 
the  scratch  of  a  pin  or  even  the  prick  of  a  penknife  or  the 
point  of  a  pair  of  scissors. 

Germs  of  disease  may  be  carried  by  contact  between 
healthy  and  diseased  persons.  This  is  known  as  contagion. 

O  Thus,  the  microscopic  form 


ing  ringworm  is  a  familiar 
example  of  germs  which 
have  been  carried  by  means 
of  a  razor  or  a  soiled  towel, 
or  which  come  from  han- 
dling a  stray  cat  infected 

1  It  is  not  uncommon  for  a  large 
number  of  persons  to  be  poisoned 
from  eating  ice  cream  at  some  pub- 
lic gathering.  This  is  caused  by  a 
change  in  the  milk  brought  about 
by  the  presence  of  bacteria.  The 
poisonous  product  of  their  action 
called  "  tyrotoxicon  "  may  also  be 
found  in  other  foods  which  have 
milk  as  their  basis,  such  as  cheese, 
custard,  and  so  on.  There  are  vomiting  and  purging  within  a  few  hours 
after  eating  the  food,  succeeded  by  great  nervous  prostration,  from  which 
recovery  follows  slowly. 


FIG.  194.     Different  Kinds  of 
Milk  Bacteria. 


BACTERIA  309 

with  the  same  disease.1  It  has  been  discovered  that  flies 
and  mosquitoes  sometimes  carry  the  germs  of  disease  from 
one  person  to  another.2 

Again,  disease-producing  bacteria,  as  we  have  learned, 
may  enter  the  body  with  the  air  we  breathe,  the  food  we 
eat,  and  the  water  we  drink.  Thus,  as  we  have  seen,  the 
air  may  be  infected  with  poisonous  germs  from  the  dust  of 
dried  sputa  (Sec.  237). 

1  Ringworm  may  occur  anywhere  on  the  body,  but  is  perhaps  most  com- 
mon on  the  scalp  and  face.     When  found  on  the  bearded  parts  of  the  face  it 
is  called  "  barber's  itch." 

Although  ringworm  of  the  face  is  usually  a  slight  affair,  it  ought  always 
to  be  cured  as  speedily  as  possible,  for  it  is  highly  contagious.  A  child 
with  ringworm  should  be  kept  away  from  school,  should  sleep  alone,  and 
should  have  special  towels,  soap,  and  hair- 
brush, which  the  other  children  in  the  family 
should  under  no  circumstances  be  allowed 
to  use. 

2  During   recent   years  it  has  been  dis- 
covered that  many  insects,  supposed  to  be 

harmless,  afford  one  of  the  ways  in  which      JTIG.  I0r      A  Piece  of  Hair 
infection  may  occur.     During  the  Spanish-         from  the  Scalp  infested 
American  war  of  1898  it  was  proved  that         with  a  Mold  which  pro- 
typhoid  fever  was  spread  through  the  camps          duces  Ringworm, 
by  the  agency  of  flies. 

These  insects,  bearing  typhoid  germs  on  their  feet,  would  fly  to  the  camp 
kitchens  and  there  leave  the  germs  on  the  food  prepared  for  the  soldiers. 
The  prevalence  of  this  "  camp  fever  "  among  troops  encamped  in  high  and 
seemingly  healthful  regions  puzzled  the  attending  surgeons  until  the  true 
explanation  was  discovered. 

The  mosquito  is  another  insect  known  to  transmit  certain  diseases ; 
indeed,  it  is  believed  by  many  to  be  the  principal  agent  in  the  spread  of  yel- 
low fever  and  malaria.  It  does  not  carry  the  germs  on  its  feet,  as  the  fly 
does,  but  within  itself  and  on  its  proboscis.  It  first  stings  a  sick  person, 
taking  in  the  germs  with  the  victim's  blood,  and  then  when  it  next  stings 
a  healthy  person  the  germs  are  communicated  to  the  blood  and  there 
develop  in  great  numbers  and  excite  an  attack  of  the  disease. 

In  India,  it  has  been  found  that  flies  carry  cholera  germs  in  the  same 
way,  wiping  them  from  their  feet  on  food;  and  it  is  quite  probable  that 
they  may  carry  the  germs  of  dysentery,  consumption,  and  other  diseases. 


310  OUR   BODIES  AND   HOW   WE   LIVE 

The  harmful  results  produced  by  bacteria  vary  greatly 
in  kind  and  severity.  Thus,  the  germs  of  consumption 
may  take  years  to  cause  fatal  results,  while  those  of  Asiatic 
cholera,  malignant  pustule,  and  diphtheria  may  destroy  life 
within  a  few  hours.1 

425.  How  Bacteria  may  act  in  the  Body.  Bacteria  act 
in  the  body  in  a  twofold  way. 

First,  the  germs  themselves  multiply  in  the  body  with  incred- 
ible rapidity. 

Second,  the  products  of  bacteria,  or  their  toxins,  as  they  are 
called,  may  act  their  part  and  bring  about  a  condition  of  poisoning. 

Thus,  the  typhoid  bacilli,  contained  in  drinking  water  pol- 
luted with  wastes  from  the  bodies  of  those  who  have  had 
typhoid  fever,  may  multiply  in  the  body  for  two  weeks  or 
more  (during  what  is  called  the  "period  of  incubation"), 
but  at  the  end  of  a  limited  time  the  typhoid  toxins  assert 
themselves  and  symptoms  of  disease  appear.  The  toxins 

of  bacteria  may  enter  the  gen- 
eral blood  current  and  poison 
the  entire  system. 

The  form  of  poisoning  result- 
FIG.  196.    Bacilli,  or  Rod-Shaped    ing  frOm  the  presence  in  the 

Bacteria. 
Magnified  about  1000  diameters.  1  ^   ^^  relationship   between 

From  a  culture  obtained  in  anthrax,  the  diseases  from  which  man  suffers 
or  malignant  pustule,  of  the  face.  and  thoge  tQ  wMch  ^^  ^  ^Ue 
Diseased  hides  carry  this  micro-  .  _  ,  .  ~  , 

organism  and  thus  may  occasion  1S  interesting  and  important.  Cats, 
this  fatal  disease  among  those  who  rabbits,  and  dogs,  as  well  as  children, 
handle  hides  and  wool.  suffer  from  diphtheria  and  scarlet  fever. 

Animals  may  acquire  these  diseases 

from  sick  children  and  in  turn  transmit  them  to  healthy  children.     Both 

man  and  the  lower  animals  suffer  from  tuberculosis. 

Among  the  diseases  belonging  especially  to  animals,  but  which   may 

also  be  contracted  by  men,  are  hydrophobia,  anthrax  or  malignant  pustule, 

glanders,  and  foot-and-mouth  disease. 


BACTERIA 


FIG.  197.     Pasteur's  Midnight  Vision. 

This  picture  is  based  upon  a  photograph  of  a  painting  which  has  won 
great  fame  during  recent  years.  The  artist  has  represented  Pasteur, 
the  celebrated  scientist,  busily  at  work  in  his  laboratory,  recording  the 
results  of  his  microscopical  study  of  bacteria.  As  the  great  master 
of  modern  science  rests  for  a  moment  from  his  midnight  researches, 
he  appears  to  see  in  vision  the  victims  of  p2stilence,  famine,  and  infec- 
tious diseases  imploring  relief  from  the  good  angel  who  symbolizes  the 
wonderful  victories  won  by  Pasteur  in  combating  disease. 

Louis  Pasteur  was  born  in  Dole,  France,  in  1822,  and  died  in  1895. 


312  OUR   BODIES   AND  HOW  WE   LIVE 

blood  of  the  products  of  putrefaction  is  known  as  septicaemia, 
or  commonly,  "blood  poisoning."  This  may  result  from 
the  use  of  polluted  instruments,  hands  soiled  in  treating 
wounds,  gunshot  injuries,  and  from  many  other  causes. 

426.  Warfare  between  Bacteria  and  the  Living  Cells  of 
the  Body.    Now,  it  is  very  evident  that  the  body  must  be 

*     M  »  a^e  to  defend  itself  against  the  myr- 

ISfif         \&          iads  of   invisible  foes  which   assail 
V  •/  &r*Ji>  its  life  at  every  moment.    Otherwise 

*p*  "i&Jfa*     a/' 

t  i  JM*w^  we  s^ou^  fall  an  easy  prey  to  the 

**^*  germs  of  disease.     As  a  matter  of 

FIG.  198.    Spiral  Form  of  fact>  there  is  unceasing  warfare  be- 

Bacteria  found  in  Cholera.  ,11  •  1^1- 

tween  the  bacteria  and  their  toxins 

Magnified  about  1000  diameters.  . 

and  the   living   cells  ot    the    body. 

The  white  blood  corpuscles  appear  to  be  the  warrior  cells 
that  fight  the  battle.  A  poison  of  another  type,  called 
antitoxin,  is  formed  in  the  serum  of  the  blood,  which  may 
antagonize  the  toxins  and  destroy  their  poisonous  action.1 

DISEASES  THAT  SPREAD  AND   DISINFECTANTS 

427.  How  Disease  may  be  prevented  and  restricted.    Two 

of  nature's  most  efficient  safeguards  in  preventing  and 
restricting  disease  are  pure  air  and  pure  water.  Cleanliness, 
proper  clothing,  wholesome  food,  and  physical  exercise  all 
play  an  important  part  in  keeping  the  body  in  sound  health. 

1  Within  the  past  few  years  remarkable  progress  has  been  made  by 
tireless  scientific  workers  in  their  efforts  to  modify  the  action  of  disease- 
producing  bacteria.  For  instance,  the  toxins  of  diphtheria  germs  are 
injected  into  the  blood  of  a  horse.  In  due  time  the  antitoxin  of  the 
disease  is  removed  from  the  serum  of  the  infected  blood,  and  after  proper 
preparation  is  injected  into  the  blood  of  a  person  exposed  to  or  suffering 
from  diphtheria.  The  effect  is  to  modify  decidedly  the  action  of  the 
poisonous  germs  of  this  dread  disease. 


DISEASES   THAT   SPREAD 


313 


In  the  preceding  chapters  we  have  learned  a  few  of  the 
simplest  principles  which  underlie  the  maintenance  of  good 
'health. 

We  are  now  to  study  very  briefly  other  means  which 
are  used  to  prevent  and  restrict  the  spread  of  disease. 
One  of  the  most  common  safeguards  against  the  spread 
of  disease  is  the  use  of 
vaccination  as  a  protection 
against  smallpox  (Sec. 
256).  That  is,  persons 
who  are  vaccinated  are 
"  immune,"  as  it  is  called, 
from  smallpox,  or  have  it 
in  a  milder  form.1 

Another  very  common 
safeguard  against  the 
spread  of  contagious  dis- 
eases is  isolation.  The 
patients,  and  often  the 
family,  are  isolated  from 
other  people;  a  rigid 
system  of  nursing  is  in- 
stituted ;  a  placard  is  placed  upon  the  house ;  the  premises 
are  watched;  and  other  familiar  means  of  isolation  are 
employed. 

1  Since  the  use  of  animal  vaccine  has  taken  the  place  of  the  old-time 
arm-to-arm  vaccination,  there  is  little  or  no  danger  of  inoculating  any  kind 
of  disease  with  the  vaccine.  The  use  of  unclean  tools,  undue  exposure  to 
inclement  weather,  and  neglect  or  improper  treatment  of  the  vaccination 
wound  are  often  the  cause  of  much  unnecessary  suffering.  As  the  pro- 
tective power  .of  vaccination  gradually  becomes  weak  with  time,  it  is  wise 
to  repeat  it  every  ten  years  at  least.  Any  one  exposed  to  smallpox  ought 
always  to  be  revaccinated,  no  matter  how  recently  the  operation  may  have 
been  performed. 


FIG.  199.     Rod-Shaped  Bacteria,  or 
Bacilli,  which  cause  Lockjaw. 

Magnified  about  1000  times. 


314  °UR  BODIES   AND   HOW  WE   LIVE 

428.  Disinfection.    The  destruction  of  the  germs  of  dis- 
ease by  means  of  heat,  chemical  agents,  fumigation,  or  fresh 
air   is   known   as  disinfection.     It   is   a   most   efficient   and 
practical  means  for  preventing  the  spread  of  disease. 

Some  substances  kill  bacteria  and  are  known  as  germicides. 
Other  substances  prevent  the  development  of  bacteria 
and  resulting  septic  action,  and  these  are  called  antiseptics. 
The  word  "disinfectant"  is  often  used  with  more  or  less 
confusion  to  cover  both^these  words.1 

A  deodorant  is  a  substance  that  removes  or  conceals 
offensive  odors.  Deodorizers  are  not  necessarily  disin- 
fectants. 

429.  Some  Common  Disinfectants.    There  are  many  ways 
of  disinfecting,  and  much  interesting  research  in  this  direc- 
tion is  going  on  all  the  time.     The  destruction  of  infected 
material  by  fire  is  a  sure  but  costly  means  of  disinfection. 
Heat  in  various  forms,  as  dry  heat,  steam,  and  boiling  water, 
is  a  valuable  disinfectant  and  does  not  injure  most  fabrics. 
These  agents  are  generally  used  in  combination  with  various 
chemical  disinfectants. 

Certain  chemical  agents  that  are  capable  of  destroying 
microorganisms  are  in  general  use.  A  compound  of  mer- 
cury, called  corrosive  sublimate,  is  a  most  efficacious  and 
powerful  germicide,  but  is  exceedingly  poisonous  and  can 
be  bought  only  under  restrictions. 

1  The  sense  in  which  the  word  "  disinfectant "  is  commonly  used  is  often 
wrong.  When  people  say  they  will  "  disinfect "  something,  they  generally 
mean  that  they  will  use  some  chemical  to  destroy  a  bad  smell  or  mask  it 
by  another  bad  smell.  The  odor  in  itself  is  all  the  while  quite  harmless, 
although  disagreeable,  and  even  if  it  were  a  terrible  menace,  the  drowning 
of  it  in  another  bad  smell  would  not  lessen  the  danger.  As  a  matter  of 
fact,  many  of  the  worst  products  of  decomposition  are  odorless.  When 
people  use  the  word,  therefore,  in  this  sense,  they  should  say  "  deodorize." 


DISEASES   THAT   SPREAD  315 

Carbolic  acid,  chloride  of  lime,  permanganate  of  potash,  sulphur, 
formaldehyde  (formalin  gas),  and  various  preparations  made 
from  zinc,  iron,  and  petroleum  are  the  disinfectants  which 
are  most  used  at  the  present  time.1 

There  are  also  numerous  varieties  of  commercial  dis- 
infectants now  in  popular  use  which  the  manufacturers 
declare  to  be  efficient  germicides. 

430.  Hints  for  the  Prevention  and  Restriction  of  a  Few  of 
the  More  Common  Infectious  Diseases.    A  few  hints  and 
helps  about  the  prevention  and  restriction  of  some  of  the 
more  common  and  dangerous  infectious  diseases  should  be 
understood  by  every  pupil  in  the  elementary  grades.2 

431.  Pneumonia.     Pneumonia  is  believed  to  be  spread 
by  a  germ  which  is  in  the  sputum  of  those  who  have  the 
disease.     Care  should  always  be  taken  to  destroy  or  dis- 
infect all  sputa. 

432.  Influenza.     Influenza,  commonly  called  "grip,"  is 
now  believed  to  be  spread  by  a  germ  which  finds  its  way 
from  infected  handkerchiefs  and  other  articles  and  places 
into  the  nose,  throat,  and  air  passages  of  persons  suscep- 
tible to  this  disease. 

433.  Consumption.     Consumption  is  spread  by  the  dust 
of  dried  sputa  and  also  by  milk  and  meat  of  diseased  cattle. 

1  Sulphur  is  an  inexpensive,  convenient,  and  satisfactory  disinfectant. 
The  infected  room  is  first  tightly  closed.     The  cracks  about  the  windows 
and  doors  are  securely  plugged  with  cotton  or  rags.     The  sulphur  is  put 
into  a  metal  dish  which  rests  upon  bricks  in  a  tub  containing  an  inch  or 
two  of  water.     The  sulphur,  moistened  with  a  little  alcohol,  is  then  ignited. 
The  room  is  quickly  closed  and  should  be  kept  closed  twenty-four  hours. 

2  The  necessary  limitations  of  an  elementary  text-book  for  schools  do 
not  allow  such  a  full  treatment  of  the  prevention  and  restriction  of  infec- 
tious diseases  and  their  disinfection  as  the  subject  deserves.     For  more 
details,  consult  Conn's  Bacteria,  Yeasts,  and  Molds,  Chapters  XVI  and  XVII, 
pp.  241-266. 


OUR   BODIES  AND   HOW  WE   LIVE 


The  most  important  measure  for  the  restriction  of  consump- 
tion is  the  disinfection  or  destruction  of  all  sputa1  of  every 
consumptive  person  and  the  strict  supervision  of  all  animals 
which  furnish  food  (Sec.  237). 

434.  Scarlet  Fever.  Scarlet  fever  has  not  yet  been  iden- 
tified by  its  special  germ,  but  that  there  is  a  germ  seems 
to  be  proved  by  the  well-known  fact  that  this  disease 

can  be  communicated 
from  person  to  person. 
It  is  spread  by  the  dis- 
charges from  the  nose, 
mouth,  and  throat,  and 
probably  also  by  the 
minute  scales  and  bits 
of  dust  which  are 
thrown  off  from  the 
surface  of  the  body. 

Isolation  and  disin- 
fection are  the  meas- 
ures by  which  this 
disease  is  restricted. 

435.  Diphtheria. 
Diphtheria  is  spread 
by  the  sputa,  saliva,  and  whatever  comes  from  the  throat  and 
mouth  of  the  patient,  and  by  the  dust  which  results  from  the 
drying  of  such  substances.  The  germs  of  diphtheria  some- 
times remain  in  the  throat  weeks  after  apparent  recovery. 

1  All  persons  suffering  from  this  disease  and  who  have  a  cough  should 
carry  small  pieces  of  cloth  (each  just  large  enough  to  receive  one  sputum 
properly)  and  paraffined  paper  envelopes  or  wrappers  in  wrhich  the  cloth,  as 
soon  as  once  used,  may  be  securely  inclosed  and  with  its  envelope  burned 
at  the  first  opportunity.  These  pieces  of  cloth  must  not  be  carried  loose 
in  the  pocket  and  allowed  to  dry  after  being  used. 


FIG.  200.     Bacilli  of  Diphtheria. 
Magnified  1000  diameters. 


CARE  OF  THE  SICK  ROOM 


For  the  restriction  and  prevention  of  this  disease  isolation 
and  disinfection  are  the  important  measures,  —  isolation  of 
every  infected  person  and  thing,  and  complete  disinfection. 

436.  Typhoid  Fever.  Typhoid  fever  is  not  so  often  con- 
tracted directly  from  contact  with  the  sick  person  as  it  is 
from  the  discharges  from  the  bowels  and  kidneys.  These 
should  always  be 
properly  disinfected. 
Undisinfected  dis- 
charges, if  dried  into 
dust,  may  spread  the 
disease  through  the 
air. 

The  chief  source  of 
danger,  however,  is 
believed  to  be  drink- 
ing water  contami- 
nated by  sewage  or 
leachings  from  out- 
buildings. The  germs 
of  typhoid  fever  are 
not  always  killed  by 
freezing,  but  are  destroyed  by  boiling.  All  suspected  water 
should  be  boiled. 


FIG.  201.     Bacilli  of  Typhoid  Fever. 
Magnified  1000  diameters. 


THE    CARE    OF    THE    SICK    ROOM 

437.  Help  in  Sickness.  Every  boy  or  girl  who  is  over 
twelve  years  old  should  learn  a  few  of  the  simplest  things 
about  taking  care  of  the  sick  and  the  sick  room.  One  may 
be  called  upon  at  any  moment  to  lend  a  hand  in  nursing 
the  sick.  People  who  are  unable  to  secure  the  services  of 


318  OUR  BODIES   AND   HOW  WE   LIVE 

a  skilled  nurse  are  often  forced  for  this  or  other  reasons  to 
depend  upon  one  or  more  of  a  large  family  of  children  to 
help  in  the  sick  room. 

Pupils  should  learn,  therefore,  at  school  such  things 
about  taking  care  of  the  sick  as  may  be  easily  understood. 
Such  practical  knowledge  is  invaluable,  for  it  may  be  put 
to  a  test  at  any  moment.  Aside  from  the  satisfaction  in 
having  this  knowledge  is  the  opportunity  so  often  afforded 
to  give  substantial  help  to  those  who  need  it  in  times  of 
sickness  and  suffering. 

438.  The  Proper  Location  of  the  Sick  Room.    The  sick 
room  should  be  the  lightest  and  most  pleasant  room  in 
the  house.     Some  one  of  the  family  may  be  taken  sick  in 
some  inconvenient  room.     If  there  is  a  prospect  of  a  long 
illness,  and  it  is  possible,  get  a  room  ready  at  once  on  a 
quiet  and  sunny  side  of  the  house. 

Take  away  all  extra  carpets,  upholstered  furniture,  heavy 
curtains,  etc.  A  clean  floor,  with  a  few  rugs  to  deaden  the 
footsteps,  is  much  better  than  a  woolen  carpet.  Carpets, 
extra  clothing,  etc.,  only  absorb  impurities  and  make  the 
room  foul. 

439.  Need  of  Fresh  Air  and  Sunlight.    The  sick  room 
should  have  plenty  of  fresh  air  and  sunlight.     It  is  generally 
best  to  shade  the  room  somewhat  in  certain  diseases,  but 
we  should  let  in  all  the  sunlight  consistent  with  comfort. 
Sunlight  and  fresh  air  are  often  more  efficient  helps  than 
drugs.     They  cost   nothing  but  a  little   painstaking  and 
common  sense. 

With  a  little  care  every  sick  room  may  be  supplied  with 
pure  air.  If  you  cannot  do  anything  else,  cover  the  sick 
person  all  over  with  extra  bedclothes,  open  the  windows 
and  doors,  and  fan  out  the  bad  air  by  swinging  the  doors. 


CARE   OF   THE   SICK   ROOM 


319 


FIG.  202.     A  Nurse  for  the  Sick  Room. 


320  OUR  BODIES   AND    HOW  WE   LIVE 

Be  sure  to  avoid  draughts  of  cold  air.     Have  a  thermome- 
ter and  keep  the  temperature  as  the  doctor  directs. 

440.  Hints  for  the  Care  of  the  Sick  Room.    Do  not  allow 
a  lamp  with  its  flame  turned  down  to  burn  through  the 
night.     A  close  room  with  such  an  odor  for  a  whole  night 
is  enough  to  make  a  well  person  sick.     If  there  is  no  gas 
or  electric  light,  either  use  the  lamp  as  usual  and  put  it, 
carefully  shaded,  in  an  adjoining  room,  or,  better  still,  use 
a  sperm  candle  for  a  night  light. 

Care  must  be  taken  to  protect  the  patient  from  any 
noise  which  may  disturb  him,  such  as  the  noise  of  passing 
steam  and  electric  cars,  heavy  teams,  and  playing  children. 

Keep  a  sick  room  neat  and  trim.  Remove  at  once  all 
excreta  and  other  offensive  matters.  Never  allow  such 
things  to  remain  even  for  a  short  time  in  the  room.  In 
many  diseases,  especially  scarlet  fever,  diphtheria,  and  con- 
sumption, use  pieces  of  old  linen  instead  of  handkerchiefs, 
and  burn  them  as  soon  as  they  are  used.  Carelessness  in 
this  matter  often  spreads  contagious  diseases. 

441.  Additional  Hints  and  Helps.    Change  the  clothes  of 
the  bed  and  of  the  patient  often.     Do  not  let  such  cloth- 
ing be  put  away  in  a  closet  with  others.     Put  it  to  soak 
at  once  in  boiling  water  with  some  disinfectant  added  if 
necessary.     The  fresh  sheets  and  pillow  cases  should  be 
thoroughly  dry  and  warm  and  never  damp. 

Do  not  make  a  great  show  of  bottles  of  medicines,  spoons, 
glasses,  etc.,  carefully  spread  out  on  the  table.  Keep  all  such 
things,  except  those  absolutely  necessary,  in  an  adjoining 
room.  To  a  patient  not  used  to  sickness,  a  formidable  array 
of  drugs  and  apparatus  is  apt  to  be  discouraging.  Some 
simple  thing  like  an  orange,  a  tiny  bouquet  of  favorite 
flowers,  or  one  or  two  playthings  may  take  their  place. 


CARE   OF   THE   SICK  ROOM  321 

442.  Whispering  in  the  Sick  Room.    Never  get  behind 
the  door,  in  a  corner,  or  in  an  adjoining  room  and  whisper. 
It  will  fret  a  well  person,  to  say  nothing  of   its  hurtful 
effects  upon  a  sufferer  whose  nerves  may  be  sensitive  to 
the  faintest  noise. 

Whatever  must  be  said,  say  it  openly  and  aloud.  How 
often  a  sudden  turn  in  bed  or  a  quick  glance  of  inquiry 
shows  that  whispering  is  doing  harm ! 

If  the  patient  is  in  his  right  mind,  answer  his  questions 
plainly  and  truthfully.  It  may  not  be  best  to  tell  all  the 
truth,  but  nothing  is  gained  by  trying  to  avoid  a  straight- 
forward reply. 

443.  Other  Suggestions  for  taking  care  of  Sick  People. 
Do  not  allow  yourself  to  take  a  nap  while  watching.     Get 
a  breath  of  fresh  air  or  take  a  bit  of  food  or  hot  drink,  if  you 
begin  to  feel  drowsy.     A  good  lunch  after  midnight  and  a 
brief  period  of  rest  will  greatly  relieve  the  tired  and  sleepy 
feeling. 

If  a  physician  is  employed,  carry  out  his  orders  to  the 
very  letter  as  long  as  he  visits  you.  Make  a  note  of  his 
directions  on  a  slip  of  paper.  Make  brief  memoranda  of 
exactly  what  you  do,  such  as  the  precise  time  of  giving 
medicines,  the  quantity  and  kind  of  nourishment,  and  an 
exact  record  on  the  temperature  chart.  This  should  always 
be  done  in  serious  cases,  and  especially  by  night  watchers. 
Then  there  is  no  guesswork.  All  such  things  are  valuable 
helps  to  the  doctor. 

Above  all,  let  there  be  cool,  wise  heads,  willing  hands, 
loving  hearts,  and  a  great  deal  of  common  sense  on  the 
part  of  helpers  in  the  sick  room. 

444.  Nursing  in  Contagious  and  Infectious  Diseases.     On 
the  physician  rests  a  great  responsibility  in  the  care  and 


322  OUR    BODIES   AND    HOW   WE    LIVE 

thorough  isolation  of  those  who  are  suffering  from  the 
various  kinds  of  infectious  and  contagious  diseases. 

Next  to  the  doctor  much  depends  upon  the  person  who 
has  charge  of  nursing  the  patient.  Those  who  nurse  the 
sick  should  see  to  it  that  their  persons  and  clothing  are 
kept  surgically  neat  and  clean.  The  trained  nurse,  for 
instance,  wears  a  cap  to  protect  her  head,  for  it  is  known 
that  the  hair  makes  a  good  lodging  place  for  bacteria. 

The  face,  hair,  and  hands  should  be  carefully  washed 
with  some  disinfectant,  especially  after  handling  the  person, 
the  bedding,  or  the  clothing  of  the  patient.  Rigid  cleanli- 
ness of  the  finger  nails  is  necessary.  Nurses  should  change 
the  clothing  worn  in  the  sick  room  when  they  leave  the 
room  to  mingle  with  the  family  or  to  walk  on  the  street 
for  exercise. 

445.  Hints  on  nursing  Contagious  and  Infectious  Diseases. 
Strip  the  room  of  superfluous  rugs,  carpets,  and  furniture. 
Isolate  two  rooms  if  possible,  and  have  these,  if  convenient, 
at  the  top  of  the  house. 

The  most  scrupulous  care  should  be  taken  in  regard  to 
cleanliness.  Old  pieces  of  linen,  cheese  cloth,  and  paper 
napkins  should  be  used  whenever  convenient  or  necessary 
and  then  burned  at  once.  All  soiled  clothing  that  cannot 
well  be  burned  should  be  put  to  soak  at  once  in  disinfect- 
ants and  afterwards  boiled  apart  from  the  family  wash. 
Dishes  and  all  utensils  should  be  kept  scrupulously  clean 
by  frequent  boiling. 

For  the  bed  and  person  old  and  worn  articles  of  clothing 
that  can  be  destroyed  should  be  worn  as  far  as  possible. 
Tack  sheets,  wet  in  some  proper  disinfectant,  to  the  outer 
frame  of  the  sick-room  door.  Boil  these  sheets  every  third 
or  fourth  day  (Sees.  430-436). 


CARE   OF   THE   SICK  ROOM  323 

In  case  of  diseases  to  which  the  young  are  very  sus- 
ceptible, send  the  children  who  have  not  been  attacked,  if 
possible,  to  other  houses  where  there  are  no  children.1 

1  There  are  a  few  simple  rules  whose  observance  will  reduce  the  chances 
of  contagion.  These  rules  should  be  followed  by  all,  but  it  is  particularly 
important  that  children  in  every  household,  and  especially  children  in  schools, 
should  be  taught  their  significance.  The  most  important  rules  are : 

Do  not  spit  on  the  floor.  Do  not  wet  the  fingers  in  the  mouth  for  the 
purpose  of  turning  the  leaves  of  books,  especially  library  or  school  books, 
inasmuch  as  book  leaves  are  sometimes  the  lurking  places  of  disease- 
producing  bacteria. 

Books  used  by  children  recovering  from  diphtheria  or  scarlet  fever 
and  then  returned  to  a  public  library  may  distribute  disease  through  a 
community. 

Do  not  put  pencils  in  the  mouth.  Do  not  put  money  in  the  mouth. 
This  is  extremely  important,  because  money  is  liable  to  come  in  contact 
with  all  sorts  of  people  and  to  become  contaminated  with  many  kinds  of 
disease-producing  bacteria. 

Do  not  put  into  the  mouth  anything  that  another  person  has  had  in  his 
mouth.  This  refers  to  gum,  apple  cores,  candy,  wrhistles,  bean  blowrers, 
drinking  cups,  etc. 

In  towns  where  the  school  officials  furnish  supplies  children  should  be 
cautioned  against  putting  into  their  mouths  articles  belonging  to  other 
children. 

Turn  the  face  aside  from  others  when  coughing.  This  will  sometimes 
prevent  contagion  passing  from  one  person  to  another,  inasmuch  as  the 
breath  in  coughing  distributes  disease  germs. 

Always  be  particular  about  personal  cleanliness,  frequently  washing  the 
face  and  hands. 

Even  a  knife  or  a  spoon  coming  from  the  sick  room  should  be  placed  in 
boiling  water  before  it  is  used  by  any  other  person.  Water  that  is  simply 
hot  is  not  sufficient  for  this  purpose.  The  water  must  be  boiling,  and  it  is 
better  if  the  articles  are  placed  in  the  water  and  the  water  boiled  for  five 
or  ten  minutes  before  they  are  taken  out  to  be  used.  — Adapted  from 
Conn's  Bacteria,  Yeasts,  and  Molds. 


324  OUR  BODIES   AND   HOW  WE   LIVE 


QUESTIONS  ON  THE  TEXT 

I.  What  change  may  occur  in  various  kinds  of  food  in  hot  weather  ? 
2.  To  what  are  these  changes  due  ?     3.  What  are  some  of  the  names 
given  to  these  living  organisms  ?     4.  What  are  bacteria  ?     5.  How  do 
bacteria  reproduce  themselves?     6.  State  briefly  the  importance  of 
the  work  done  by  bacteria.     7.  What  can  you  say  about  disease- 
producing  bacteria  ?     8.  Describe  the  action  of  bacteria  upon  food. 
9.  How  may  bacteria  gain  access  to  the  body?     10.  How  may  disease 
be  spread  by  contagion? 

II.  Give  illustrations  to  show  how  diseases  maybe  spread  by  insects. 
12.   In  what  two  ways  may  bacteria  act  in  the  body?     13.   Illustrate 
the  distribution  of  bacteria  by  describing  how  typhoid  fever  spreads- 
14.  What  is  meant  by  septicaemia,  or  blood  poisoning  ?     15.  How  does 
the  body  defend  itself  against  bacteria?     16.  What  are  the  two  great 
safeguards  against  the  spread  of  disease?     17.  What  other  means 
are  used  to  prevent  and  restrict  the  spread  of  disease?     18.  What 
is  disinfection?     19.  Define  germicides,  antiseptics,  and  deodorants. 
20.  Explain  briefly  the  use  of  fire  and  the  various  forms  of  heat  as 
disinfectants. 

21.  What  are  some  chemical  agents  that  are  used  as  disinfectants? 

22.  What  can  you  say  about  the  spread  of  pneumonia  and  influenza  ? 

23.  Describe  in  some  detail  the  means  used  to  restrict  the  spread  of 
consumption.     24.  What  can  you  state  about  the  spread  of  scarlet 
fever?     25.   How  may  diphtheria  be  spread,  and  what  are  the  two 
important  measures   used    to  restrict    the    disease?     26.  How  may 
typhoid  fever  be  spread  ?     27.  Why  should  young  people  learn  to  take 
care  of  the  sick  ?     28.  Describe  the  proper  location  of  the  sick  room. 
29.  Explain  the  need  of  fresh  air  and  sunlight.     30.  Mention  some 
practical  points  about  the  care  of  the  sick  room. 

31.  What  additional  hints  concerning  the  sick  room  can  you  give  ? 

32.  What  are  some  of  the  ill  effects  of  whispering  in  the  sick  room  ? 

33.  What  other  suggestions  about  taking  care  of  sick  people  can 
you  give  ?     34.  What  are  some  precautions   necessary  to  be    taken 
by  nurses  in   infectious  and  contagious  diseases?     35.  Give  some 
suggestions  about  nursing   patients   suffering  from  contagious  and 
infectious  diseases. 


APPENDIX 


THE   STUDY   OF   PHYSIOLOGY   IN   ELEMENTARY 
SCHOOLS 

Within  a  few  years  the  methods  of  teaching  physiology  have 
changed  radically  for  the  better.  No  progressive  teacher  of  to-day 
rests  content  with  merely  teaching  the  text.  The  text-book  has  come 
to  be  regarded  only  as  a  convenient  helper,  a  crutch  to  lean  upon,  a 
basis  upon  which  to  build  good  work.  Hence  every  topic  in  this 
text-book  should  be  more  fully  explained,  amplified,  and  illustrated. 
To  secure  the  best  results,  a  great  variety  of  exercises  should  be 
arranged  to  help  fasten  the  facts  in  the  pupil's  memory  and  to  make 
the  study  interesting,  useful,  and  practical.  The  author  begs  leave 
in  this  connection  to  present  in  outline  a  few  of  the  more  practical 
helps  which  have  been  utilized  and  tested  in  conducting  classes  in 
elementary  physiology. 

1.  Preliminary  Oral  and  Written  Work.  Teachers  should  give 
their  pupils  a  pleasant  introduction  to  the  work  by  a  familiar  talk 
on  the  general  subject  of  studying  physiology  and  hygiene.  One 
or  two  lessons  may  be  devoted  to  this  topic.  A  carefully  prepared 
outline  should  be  written  on  the  blackboard  with  catchwords  enough 
to  allow  the  pupil  to  follow  readily.  Impromptu  questions  and 
answers  should  be  encouraged.  The  outline  should  be  copied  by 
the  pupils  into  blank  books  with  such  catchwords  as  may  make  the 
meaning  clear  for  future  reference.  The  several  points  should  be 
clinched  with  many  homely  and  striking  bits  of  information  and 
picturesque  illustrations.1 

1  A  suggestive  blackboard  outline  to  cover  this  point,  together  with  a  more 
detailed  discussion  of  the  several  topics  treated  in  this  Appendix,  may  be  found  in 
the  author's  little  book  entitled  "  How  to  Teach  Physiology,"  a  handbook  for 
teachers.  A  copy  of  this  pamphlet  will  be  sent  postpaid  on  receipt  of  ten  cents  to 
any  address  by  the  publishers  of  this  book. 

325 


326  OUR   BODIES   AND    HOW  WE    LIVE 

2.  The  Use  of  a  Blank  Book.     Every  teacher  of  physiology  will 
find  a  blank  book  of  great  service.     Into  this  may  be  copied  a  great 
variety  of  working  memoranda,  apt  quotations,  lists  of  special  topics 
and  subtopics,  additional  practical  experiments  obtained  from  other 
teachers  and  text-books,  examination  and  test  questions,  blackboard 
sketches,  etc.,  gathered  from  many  and  varied  sources.     Everything 
should  be  numbered  and  labeled  for  quick  reference,  and  cross  refer- 
ences should  be  made  to  the  home  text-book. 

An  extra  copy  of  the  school  text-book  should  be  kept  for  home 
use.  Insert  blank  paper  leaves  or  utilize  blank  margins  of  pages  to 
insert  catchwords  and  cross  references  to  all  sorts  of  illustrative  mate- 
rial which  may  be  collected  and  arranged  from  sundry  notebooks, 
scrapbooks,  and  newspaper  clippings. 

3.  The  Use  of  a  Scrapbook.     A  well-kept  and  indexed  scrapbook 
is  also  extremely  useful  to  the  busy  teacher  of  physiology.     Clippings 
of  odd  and  interesting  facts   and  instructive  matter  pertaining  to 
physiology  and  health,  which  have  been  culled  from  newspapers, 
magazines,  and  periodicals  generally,  may  conveniently  be  preserved 
in  this  manner.     An  old  geography  or  a  discarded  account  book  will 
answer  every  purpose.    Cross  references  should  be  made  to  the  home 
text-book  and  to  the  blank  book. 

4.  How  Teachers  may  utilize  the  Blackboard.     The  blackboard  is 
very  helpful  in  teaching  physiology.     It  should  be  utilized  for  health 
maxims,  golden  texts,  topics  for  oral  and  written  work,  review  analy- 
ses, tables,  and  references  of  various  kinds.     The  teacher  can  readily 
learn  to  make  the  necessary  sketches  rapidly  and  correctly  on  the 
blackboard.     Sketches  which  take  much  time  and  pains  should  be 
made  before  or  after  the  school  session.     Offhand  sketches  should 
be  used  every  day  and  should  be  drawn  in  the  presence  of  the  class 
to  illustrate  sundry  points  in  the  text. 

5.  How  Pupils  may  utilize  the  Blackboard.     The  pupils  themselves 
should  be  taught  to  do  a  goodly  amount  of  work  on  the  blackboard. 
Sketches   of   bones  (Fig.    12,   p.   19),  diagrams   of  the  circulation 
(Fig.  92,  p.  149),  tables  of  bones  (p.  42),  etc.,  should  be  put  upon 
the  blackboard  by  the  pupils  with  as  much  confidence,  neatness, 
and  rapidity  as  they  would  use  in  writing  out  an  exercise  in  language 
or  in  doing  an  example  in  arithmetic.     Sketches  which  demand  extra 
time  and  labor  may  be  drawn  before  or  after  the  regular  session  and 
allowed  to  remain  on  the  board  as  long  as  convenient. 


APPENDIX  327 

So  simple  a  matter  as  using  red  crayon  for  the  arteries,  blue  for 
the  veins,  yellow  for  the  nerves,  and  white  for  the  bones  will  add 
much  to  the  attractiveness  of  the  work.  Duplicate  copies  of  all  this 
blackboard  work  may  be  used  by  the  pupils  to  illustrate  their  own 
blank  books.  (See  also  Figs.  65,  p.  103;  77  and  78,  pp.  118  and 
119;  and  105,  p.  168.) 

6.  Books  for  Collateral  Reading  and  Reference.     A  certain  number 
of  books  on  physiology  and  hygiene  are  useful  for  collateral  reading 
and  quick  reference.     Their  number  and  character  will  depend  largely 
upon  the  grade  of  the  pupil  for  whom  they  are  intended.     Second- 
hand text-books  of  the  same  grade  as  the  class  text-book  are  easily 
purchased  of  dealers.     Such  books  may  be  kept  on  the  teacher's  desk 
for  the  pupil  to  consult  in  school  hours  or  to  carry  home  and  read  at 
leisure.     Passages  in  these  books   which  are  interwoven  with   the 
topics  under  consideration  should  be  marked  with  colored  pencil  by 
the  teacher  to  aid  the  pupil  in  his  researches. 

7.  The  Use  of  Homemade  Apparatus.     It  is  scarcely  advisable  to 
recommend  the  use  of  a  manikin,  separate  bones,  a  skeleton,  and 
physiological  charts  for  use  in  the  elementary  grades.     As  a  matter 
of  fact,  very  few  school  officials  can  afford  to  furnish  their  school- 
rooms with  such  useful  but  costly  material.     Fortunately,  however, 
most  teachers  can  copy  passably  well  illustrations  taken  from  other 
books.     With  a  little  painstaking  and  ingenuity  the  teacher  of  even 
the  more  remote  district  schools  can  make  a  few  charts  which  will 
prove  effective  helps  toward  making  the  work  successful.     For  this 
purpose,  white  cardboard  or  even  manila  paper  may  be  used  upon 
which  to  make  the  sketches  in  colored  inks  or  crayons.     For  apparatus 
with  which  to  hang  or  construct  charts,  eyelets,  curtain  fixtures,  stout 
cords,  clothespins,  telephone  wire,  pasteboard  boxes,  colored  paper, 
and  many  other  things  have  been  used. 

For  the  encouragement  of  teachers  in  remote  sections  it  may  be 
well  to  mention  the  fact  that  many  eminent  scientists  do  not  hesitate 
to  make  very  crude  drawings  on  the  blackboard,  and  often  resort  to 
the  use  of  their  own  hats,  umbrellas,  canes,  handkerchiefs,  pocket- 
knives,  and  other  articles  to  illustrate  their  lectures. 

It  is,  perhaps,  unnecessary  to  state  that  the  collection  and  prepara- 
tion of  the  working  material  which  has  been  suggested  may  demand 
much  labor  and  patience  for  the  first  year,  but  that  it  can  be  kept  for 
use  in  succeeding  classes. 


328  OUR  BODIES   AND   HOW  WE   LIVE 

8.  Importance    of    Experiments    in    teaching    Physiology    in   Ele- 
mentary Schools.     The  subject-matter  as  set  forth  in  the  preceding 
chapters  of  this  book  should  be  carefully  studied  and  read.     At  the 
same  time,  however,  the  topics  studied  should  be  amplified  and  made 
more  interesting  and  practical  by  a  series  of  experiments  given  in 
connection  with  the  several  chapters,  a  goodly  show  of  specimens, 
and  a  certain  amount  of  microscopical  work. 

The  experimental  method  of  teaching  the  sciences  rivets  the  atten- 
tion and  arouses  and  keeps  alive  the  interest  of  the  young  student ; 
in  fact,  it  is  the  only  true  method  of  cultivating  a  scientific  habit  of  study. 
Every  teacher  knows  that  pupils  gain  a  far  better  knowledge  and  keep 
up  a  livelier  interest  in  their  work,  if  they  are  able  to  see  with  their  own 
eyes  and  to  do  with  their  own  hands  that  which  serves  to  illustrate  the 
particular  branch  of  science  in  which  they  are  engaged.1 

9.  The  Use  of  Inexpensive  Apparatus.     It  will  be  noted  that  most 
of  the  experiments  which  have  been  suggested  in  the  preceding  chap- 
ters of  this  book  can  be  performed  with  very  simple  and  often  crude 
homemade  apparatus.     This  plan  has  been  followed  by  the  author : 
first,  because  he  fully  realizes  the  limitations  of  the  subject;  and 
secondly,  because  he  wishes  to  emphasize  the  fact  that  expensive  and 
complicated  apparatus  is  by  no  means  necessary  to  illustrate  the  great 
principles  of  anatomy  and  physiology. 

In  schools  in  which  both  the  funds  and  the  time  for  experimental 
work  are  limited,  the  zeal  and  ingenuity  of  teachers  and  students  are 
often  put  to  a  severe  test.  Fortunately,  a  very  little  money  and  a 
great  deal  of  ingenuity  and  patience  will  do  much  towards  providing 
a  working  supply  of  apparatus. 

10.  The  Microscope  in  Elementary  Schools.     For  elementary  class 
work  a  moderate-priced  but  well-made  and  strong  microscope  should 
be  provided.     If  the  school  does  not  own  or  cannot  afford  to  buy  a 
microscope,  the  loan  of  an  instrument  should  be  obtained  for  at  least 
a  few  weeks  from  some  person  in  the  neighborhood.2 

1  A  number  of  books,  prepared  for  the  use  of  teachers  and  students  who  wish  to 
supplement  the  text -book  with  experimental  work,  have  been  recently  published.    Of 
these  books  the  teacher  is  advised  to  use  James  E.  Peabody's  Laboratory  Exercises 
in  Anatomy  and  Physiology  (Henry  Holt  &  Co.,  New  York,  publishers ;  price  60 
cents);  and  Bertha  M.  Brown's  Physiology  for  the  Laboratory  (Ginn  &  Company, 
publishers;  price  75  cents). 

2  The  catalogues  of  scientific-instrument  makers  usually  furnish  a  list  of  the 
requisite  materials  for  experimental  use  or  the  titles  of  handbooks  which  describe 


APPENDIX 


329 


The  appearance  of  the  various  structures  and  tissues  of  the  human 
body  as  revealed  by  the  microscope  possesses  a  curious  fascination 
for  every  observer,  especially  for  young  students.  No  one  ever  forgets 
the  first  look  at  a  drop  of  blood,  or  the  circu- 
lation of  blood  in  the  web  of  a  frog's  foot  as 
revealed  by  the  microscope. 

11.  Dissection  in  Elementary  Schools.     A 
few  simple  dissections  which   can  be   made 
with  fresh  beef  joints  and  legs  of  chickens 
and  turkeys  will  answer  every  purpose  in  the 
elementary  grades.    A  discreet  teacher  should 
rarely  advise  his  pupils  to  dissect  a  dead  cat, 
dog,  frog,  or  any  other  animal.     Instead  of 
actually  dissecting,  the  pupils  should  examine 
specimens  or  certain    parts   previously  dis- 
sected by  the  teacher,  —  as  the  muscles  and 
joints  of  a  sheep,  the  heart  of  an  ox,  the  eye 
of  a  codfish,  and  so  on. 

12.  Teaching  Surface  Anatomy  and  Land- 
marks of  the  Body.     In  elementary  work  it  is 

only  fair  to  state  that  comparatively  few  points  FIG.  203.  A  Compound 
concerning  the  surface  anatomy  and  land-  Microscope, 

marks  of  the  body  can  be  defined  or  located 

with  precision.  A  certain  amount  of  work  in  this  direction  can,  how- 
ever, be  done,  even  in  elementary  schools,  with  ingenuity,  patience, 
and  a  due  regard  for  the  feelings  of  all  concerned.  For  example,  the 
student  may  be  taught  to  examine  the  muscles  and  other  parts  of  his 
own  face,  his  teeth,  tongue,  and  palate,  and  the  bones  and  muscles  of 
his  shoulders  and  limbs.  Two  friends  may  thus  work  together,  each 
serving  as  a  model  to  the  other.1 

the  use  of  the  various  microscopes  of  standard  make.  For  detailed  suggestions  in 
regard  to  the  manipulation  and  use  of  the  microscope  the  student  is  referred  to  any 
of  the  standard  works  on  the  subject. 

For  the  names  and  addresses  of  firms  that  deal  in  microscopes  and  apparatus 
for  experiments  consult  the  advertising  pages  of  leading  educational  publications. 

1  On  pages  415-419  in  the  author's  Practical  Physiology  may  be  found  a  syllabus 
of  a  brief  course  of  study  concerning  surface  anatomy  and  landmarks  of  the  body. 


GLOSSARY  OF  TECHNICAL  TERMS 


Many  words  that  are  defined  or  explained  as  they  occur  in  the  text  of  this  book,  or  the 
meaning  of  which  is  readily  understood,  have  been  omitted  in  this  Glossary. 


Ab-do'men  (Lat.).  The  largest  cav- 
ity of  the  body,  containing  the 
liver,  the  stomach,  the  intestines, 
and  other  organs. 

Ab-sorb'ent  (Lat.  absorbere,  to  suck 
up).  An  organ  or  part  that  ab- 
sorbs; a  lymphatic  vessel. 

Ab-sorp'tion.  The  process  of  suck- 
ing up  nutritive  or  waste  mat- 
ters by  the  blood  vessels  or 
lymphatics. 

Ac-com'mo-da'tion  of  the  eye.  The 
alteration  in  the  shape  of  the 
crystalline  lens  which  adjusts 
the  eye  for  near  vision. 

Ac-e-tab'u-lum  (Lat.  acetabulum,  a 
vinegar  cup).  The  cup-shaped 
cavity  of  the  innominate  bone 
which  receives  the  head  of  the 
femur. 

A-cro'mi-on  (Gr.  &Kpos,  extreme,  and 
wyiios,  the  shoulder).  The  part  of 
the  scapula  forming  the  tip  of  the 
shoulder. 

Al-bu'men  (Lat.  albumen,  white  of 
egg) .  Formerly  used  as  a  synonym 
for  proteid. 

Al-bu'min  (albumen  and  -in}.  A 
class  of  proteids,  as  egg  albumin. 


Ari-men/ta-ry  (Lat.  alere,  to  nour- 
ish). Pertaining  to  aliment,  or  food. 

Ari-men'ta-ry  ca-nar.  The  diges- 
tive tube  from  the  lips  to  the  end 
of  the  rectum,  with  its  accessory 
glands. 

Al'ka-lies  (Arabic  a/,  the,  and  qally, 
ashes  of  saltwort).  Certain  sub- 
stances, such  as  soda,  potash,  and 
the  like,  which  unite  with  acids  to 
form  salts. 

A-mce'ba  (Gr.  d/*oij3^,  a  change). 
A  single-celled,  protoplasmic  ani- 
mal, which  has  the  power  of  chang- 
ing its  form  by  protrusions  and 
withdrawals  of  its  substance. 

A-mce'boid.  Like  an  amoeba  in 
form  or  in  movement. 

An'aes-thet'ic  (Gr.  dv-,  not,  and  ai<r0T}- 
r6s,  perceptible).  A  substance 
which  produces  insensibility  to 
pain  or  to  touch,  as  chloroform, 
ether,  etc. 

An'ti-dote  (Gr.  dvrl,  against,  and 
5or6s,  given).  A  substance  given 
to  prevent  or  counteract  the 
action  of  a  poison. 

An'ti-sep'tic  (Gr.  dvrl,  against,  and 
<nr}ir€iv,  to  make  rotten).  A  remedy 


332 


OUR  BODIES   AND   HOW  WE   LIVE 


or  agent  which  prevents  the  devel- 
opment of  bacteria,  or  prevents 
the  growth  of  bacteria  upon  which 
putrefaction  depends. 

An'ti-tox'in  (Gr.  avri,  against,  and 
toxin}.  A  substance  which  neu- 
tralizes the  action  of  the  toxins  of 
bacteria.  Antitoxins  are  used  in 
the  treatment  of  certain  infectious 
diseases,  as  diphtheria. 

An'trum  (Gr.  Avrpov,  a  cave).  The 
cavity  in  the  upper  jaw. 

Ap'pa-ra'tus.  Used  to  designate 
collectively  organs  which  perform 
a  certain  function. 

Ap-pen'di-ci'tis  (Lat.  appendix}. 
Inflammation  of  the  appendix 
vermiformis  of  the  caecum. 

A'que-ous  hu'mor  (Lat.  aqua,  water). 
The  watery  fluid  occupying  the 
space  between  the  cornea  and 
the  crystalline  lens  of  the  eye. 

Ar'bor  vi'tse  (Lat.  arbor  vitae,  tree 
of  life).  A  name  given  to  the 
treelike  appearance  of  a  section 
of  the  cerebellum. 

A-re'o-lar  tis'sue  (Lat.  areola,  dim. 
of  area,  a  piece  of  open  ground). 
Connective  tissue  containing  small 
spaces. 

Ar-tic'u-la'tion  (Lat.  articulus,  a 
joint).  The  more  or  less  mov- 
able union  of  bones,  etc. ;  a  joint. 

A-ryt'e-noid  car'ti-lag-es  (Gr.  apt- 
Taiva,  a  ladle).  Two  small  car- 
tilages of  the  larynx,  resembling 
the  mouth  of  a  pitcher. 

As-phyx'i-a  (Gr.  d-,  without,  and 
ffQtfciv,  to  pulsate).  Suffocation. 
The  suspension  of  vital  phenom- 


ena wrhen  the  lungs  are  deprived 

of  oxygen. 
As-sim'i-la'tion   (Lat.   ad,  to,   and 

similis,  like).     The  conversion  of 

food  into  living  tissue. 
Az'y-gos  (Gr.  d-,  without,  and  £vy6v, 

a  yoke).     Applied  to  parts  that 

are  single,  not  in  pairs. 

Ba-cillus  (Lat.  dim.  of  bacidum,  a 
staff).  A  microscopic  rod-shaped 
form  of  bacteria. 

Bac-te'ri-um,  pi.  bac-te'ri-a  (Gr. 
pa.KT-fipi.ov,  a  little  staff).  A 
microscopic  vegetable  organism. 

Bac-te'ri-cide  (bacterium  and  Lat. 
caedere,  to  kill).  An  agent  that 
destroys  bacteria. 

Blad'der  (Saxon  blcedre,  a  blister, 
a  bladder).  A  bag,  or  sac,  serving 
as  a  receptacle  of  some  secreted 
fluid,  as  the  gall  bladder,  urinary 
bladder,  etc. 

Bright's  dis-ease'.  Disease  of  the 
kidneys,  first  described  by  Dr. 
Bright,  an  English  physician. 

Cap'il-la-ry  (Lat.  capillus,  hair).  A 
minute  vessel,  as  those  that  con- 
nect by  a  network  the  arteries 
and  veins. 

Cap'sule  (Lat.  capsula,  a  little  chest). 
A  receptacle,  or  bag. 

Car'bon  di-ox'ide.  A  gas  produced 
in  the  respiration  of  animals,  and 
in  the  decay  or  combustion  of 
organic  matter.  Often  called  car- 
bonic acid  gas. 

Car'di-ac  or'i-fice  (Gr.  Kapdia,  the 
heart).  The  orifice  of  the 
stomach,  near  the  heart. 


GLOSSARY   OF   TECHNICAL  TERMS 


333 


Car'ron  oil  (from  its  use  at  the  Car- 
ron  Iron  Works).  A  mixture  of 
equal  parts  of  linseed  oil  and 
limewater. 

Car'ti-lage.  Gristle.  A  tough  but 
flexible  tissue  forming  a  part  of 
the  joints,  air  passages,  nose, 
ears,  etc. 

Car'un-cle  (lach'ry-mal)  (Lat.  ca- 
runcula,  dim.  of  caro,  flesh).  The 
small,  red,  conical-shaped  swelling 
at  the  inner  angle  of  the  eye. 

Ca'se-in  (Lat.  caseus,  cheese).  A 
proteid  substance  found  especially 
in  milk.  The  principal  ingredient 
in  cheese. 

Cell  (Lat.  cella,  a  room).  One  of  the 
ultimate  units  of  which  all  living 
bodies  are  composed.  A  granular 
mass  of  protoplasm  containing  a 
nucleus. 

Cer'e-belflum(Lat.  dim.  of  cerebrum}. 
The  part  of  the  brain  lying  below 
the  cerebrum  and  above  the  pons 
and  the  medulla  oblongata. 

Cer/e-brum(Lat.).  The  brain  proper, 
occupying  the  upper  portion  of 
the  skull. 

Chi-rop'o-dist  (Gr.  x^P,  a  hand,  and 
Trotfs,  afoot).  A  person  who  treats 
diseases  of  the  hands  and  feet. 

Chlo'ral.  A  powerful  drug  and 
narcotic  poison  used  to  produce 
sleep. 

Chlo'ro-form.  A  narcotic  poison 
generally  used  by  inhalation ;  of 
extensive  use  in  surgical  opera- 
tions to  produce  anaesthesia. 

Chor'dae  ten-di'ne-ae  (Lat.).  Ten- 
dinous cords,  connecting  the  papil- 


lary muscles  of  the  heart  with 
the  auriculo-ventricular  valves. 

Cho'roid  (Gr.  x6piov>  membrane, 
chorion,  and  eTSos,  form).  The 
middle  coat  of  the  eyeball. 

Ciri-a  (Lat.  pi.  of  cilium,  an  eyelash). 
Minute  threadlike  processes 
found  upon  the  cells  of  the  air 
passages  and  other  parts. 

Cil'ia-ry  mus'cle.  A  small  muscle 
of  the  eye  which  assists  in  accom- 
modation. 

Co-ag'u-lartion  (Lat.  coagulare,  to 
curdle).  The  process  by  which  a 
liquid  like  blood  or  milk  clots,  or 
solidifies. 

Co'ca-ine.  A  bitter,  white  sub- 
stance obtained  from  the  leaves 
of  coca,  capable  of  producing 
local  insensibility  to  pain  wrhen 
applied  to  the  surface  of  mucous 
membranes  or  injected  under  the 
skin. 

Coch'le-a  (Lat.  cochlea,  a  snail).  The 
spiral  cavity  of  the  internal  ear. 

Co'ma  (Gr.  KcD/xa,  lethargy).  A  deep 
stupor  from  which  it  is  difficult 
or  impossible  to  arouse  a  person. 

Com'mis-sure  (Lat.  com-,  together, 
and  mittere,  to  send).  A  bridge- 
like  structure  uniting  similar  parts. 

Com'press.  A  pad  or  bandage 
applied  directly  to  an  injury. 

Con'cha  (Gr.  K&yx7?*  a  mussel).  The 
shell-shaped  portion  of  the  exter- 
nal ear. 

Con-ges'tion  (Lat.  com-,  together, 
and  gerere,  to  bring).  Abnormal 
collection  of  blood  in  a  part  or 
organ. 


334 


OUR   BODIES   AND    HOW   WE   LIVE 


Con'junc-ti'va  (Lat.  com-,  together, 
and  jungere,  to  join).  A  thin 
layer  of  mucous  membrane  which 
lines  the  eyelids  and  covers  the 
front  of  the  eyeball,  thus  joining 
the  latter  to  the  lids. 

Con-ta'gion  (Lat.  com-,  together,  and 
tangere,  to  touch).  The  process 
by  which  a  specific  disease  is  com- 
municated from  one  person  to 
another,  either  by  contact  or  by 
means  of  an  intermediate  agent. 
Also  the  specific  germ,  or  virus, 
which  causes  a  communicable 
disease. 

Con'trac-til'i-ty  (Lat.  com-,  together, 
and  trahere,  to  draw).  The  prop- 
erty of  a  muscle  which  enables 
it  to  draw  its  extremities  closer 
together. 

Con'vo-lu'tions  (Lat.  com-,  together, 
and  volvere,  to  roll).  Tortuous 
foldings,  as  those  of  the  external 
surface  of  the  brain. 

Co-bYdi-na'tion.  The  manner  in 
which  different  organs  of  the  body 
are  made  to  work  together. 

Cor'ne-a  (Lat.  cornu,  a  horn).  The 
transparent  hornlike  substance 
which  covers  a  part  of  the  front 
of  the  eyeball. 

Cor'pus-cle  (Lat.  corpuscuhim,  dim. 
of  corpus,  a  body).  A  small  body 
or  particle. 

Cri'coid  (Gr.  /cpkos,  a  ring,  and  etSos, 
form).  A  cartilage  of  the  larynx 
resembling  a  seal  ring  in  shape. 

Crys'tal-line  lens  (Gr.  K-p&rraXXos, 
ice,  crystal).  One  of  the  refrac- 
tive media  of  the  eye ;  a  double- 


convex  body  situated  in  the  front 

part  of  the  eyeball. 
Cu'ti-cle  (Lat.  cuticula,  dim.  of  cutis). 

Scarfskin ;  the  epidermis. 
Cu'tis  (Lat.  cutis,  the  skin).     The 

true  skin,  also  called  the  dermis. 

De-gen'er-a  't  ion  ( Lat .  de,  from,  down, 
and  genus,  race).  A  morbid  proc- 
ess in  the  structure  of  an  organ 
by  which  its  tissues  are  converted 
into  some  inert  substance. 

Deg'lu-ti'tion  (Lat.  deglutire,  to 
swallow).  The  act  of  swallowing. 

Den'tine  (Lat.  dens,  a  tooth).  The 
hard  substance  which  forms  the 
greater  part  of  the  tooth ;  ivory. 

De-o'dor-ant  (Lat.  de,  without,  and 
odorare,  to  smell).  A  substance 
which  removes  or  conceals  offen- 
sive odors. 

Dex'trin  (Lat.  dexter,  right).  A 
soluble  carbohydrate  into  which 
starch  is  converted  by  diastase 
or  dilute  acids  or  by  dry  heat. 

Dex'trose'  (Lat.  dexter,  right). 
Grape  sugar. 

Dis'in-fect'ants.  Agents  used  to 
destroy  the  germs  of  disease,  fer- 
mentation, and  putrefaction. 

Dislo-ca'tion  (Lat.  dis-,  contrary  to, 
and  locare,  to  place).  An  injury 
to  a  joint  in  which  the  bones  are 
displaced  or  forced  out  of  their 
sockets. 

Dis-sec'tion  (Lat.  dis-,  apart,  and 
secare,  to  cut).  The  cutting  up  of 
an  animal  to  learn  its  structure. 

Du'o-de'num  (Lat.  duodent,  twelve 
each).  The  first  division  of  the 


GLOSSARY  OF  TECHNICAL  TERMS 


335 


small  intestines,  about  twelve 
fingers'  breadth  long. 
Dys-pep'si-a  (Gr.  5&r-,  difficult,  and 
irtiTT€i.v,  to  digest).  The  name 
given  to  certain  diseases  of  the 
digestive  organs. 

Ef-flu'vi-a  (Lat.  effluere,  to  flow 
out).  Offensive  odors  coming 
from  the  body,  and  from  decay- 
ing animal  or  vegetable  sub- 
stances. 

Ere-ment  One  of  the  simplest 
parts  of  which  anything  consists. 

E-lim'i-na'tion  (Lat.  e,  out,  and 
limen,  a  threshold).  The  act  of  ex- 
pelling waste  matters.  Signifies 
literally  "  to  throw  out  of  doors." 

E-met'ic  (Gr.  ^eTi/c6$,  causing  vomit- 
ing). An  agent  which  causes 
vomiting. 

E-muTsion  (originally  milky  juice 
from  almonds  bruised  in  water; 
from  Lat.  emulgere,  to  milk  out). 
A  preparation  consisting  of  a 
liquid,  usually  water,  containing 
an  insoluble  substance,  as  fat,  in 
suspension. 

E-nam'el  (Fr.  en,  in,  and  email, 
enamel).  Dense  material  cover, 
ing  the  crown  of  a  tooth. 

Ep'i-dem'ic  (Gr.  tirl,  upon,  and 
STJ/XOS,  the  people).  A  disease 
which  affects  large  numbers,  or 
which  spreads  over  a  wide  area. 

Ep'i-glotftis  (Gr.  tirl,  upon,  and 
7\wTT*s,  the  entrance  to  the  wind- 
pipe). A  leaf -shaped  lid  which 
covers  the  top  of  the  larynx  dur- 
ing the  act  of  swallowing. 


Ep'i-lep'sy  (Gr.  t-rrl,  upon,  and  \af3eiv, 
seize).  A  nervous  affection  ac- 
companied by  fits  and  sudden 
loss  of  consciousness. 

E'ther  (Gr.  aW-fip,  the  pure  upper 
air).  A  narcotic  poison.  Its  chief 
use  is  as  an  anaesthetic  in  surgi- 
•cal  operations. 

Eu-sta'chi-an  tube  (from  an  Italian 
anatomist  named  Eustachio). 
The  tube  which  leads  from  the 
throat  to  the  middle  ear. 

Ex-cre'ta  (Lat.  excernere,  to  sepa- 
rate). The  refuse  matter  which 
is  passed  from  the  body  in  any 
form. 

Ex-cre'tion  (Lat.  excernere,  to  sepa- 
rate). The  separation  from  the 
blood  of  the  waste  matters  of 
the  body;  also  the  materials 
excreted. 

Fas'ci-a  (Lzt.  fascia,  a  band).  The 
areolar  tissue  forming  layers  be- 
neath the  skin  or  between  muscles. 

Fau'ces  (Lat.).  The  part  of  the 
mouth  which  opens  into  the 
pharynx. 

Fe-nes'tra  o-valis  and  fenestra  ro- 
tun'da  (Lat.  fenestra,  a  window). 
The  oval  and  the  round  window ; 
two  apertures  in  the  bone  between 
the  tympanic  cavity  and  the  laby- 
rinth of  the  ear. 

Fer/ment  (Lat.  fermentum,  leaven). 
Any  substance  which  in  contact 
with  another  substance  is  capable 
of  setting  up  changes  (fermen- 
tation) in  the  latter,  without  itself 
undergoing  much  change. 


336 


OUR   BODIES  AND   HOW  WE   LIVE 


Fer'men-ta'tion  (Lat.  fermentum, 
leaven).  An  effervescent  change, 
as  by  the  action  of  yeast ;  in  a 
wider  sense,  the  change  of  organic 
substances  into  new  compounds 
by  the  action  of  a  ferment.  It 
differs  in  kind  according  to  the 
nature  of  the  ferment. 

Fi-briHa  (Lat.  dim.  oifibra,  a  fiber). 
A  little  fiber ;  one  of  the  longitudi- 
nal threads  into  which  a  striped 
muscular  fiber  can  be  divided. 

Fi'brin  (Lat.  fibra,  a  fiber).  A  pro- 
teid  substance  contained  in  the 
flesh  of  animals,  and  also  pro- 
duced by  the  coagulation  of  blood. 

Forii-cle  (Lat.  folliculus,  dim.  of 
follis,  a  bag).  A  little  pouch  or 
depression,  as  the  hair  follicle. 

Fo'men-ta'tion  (Lat.  f amentum,  a 
warm  lotion  or  poultice).  The 
application  of  heat  and  moisture 
to  a  part  to  relieve  pain  and  reduce 
inflammation. 

Fo-ra'men  (Lat.  forare,  to  pierce). 
A  hole,  or  an  aperture. 

Fron-  tal  si'nus  (Lat.  frons,  the  fore- 
head). A  blind  or  closed  cavity 
in  the  bones  of  the  skull  just  over 
the  eyebrows. 

Fu'mi-ga'tion  (Lat.  fumigare,  to 
smoke).  Disinfection  by  means 
of  a  vapor. 

Func'tion  (Lat.  fungi,  to  perform). 
The  normal  or  special  action  of 
a  part. 

Gan'gli-on  (Gr.  ydyy\iov,  a  tumor 
on  or  near  a  tendon).  A  collec- 
tion of  nerve  cells. 


Gel'a-tin  (Lat.  gelare,  to  congeal). 
An  albuminoid  substance  which 
dissolves  in  hot  water  and  forms 
a  jelly  on  cooling. 

Germ  (Lat.  gerrnen,  a  sprout,  bud). 
A  portion  of  matter  capable  of 
developing  into  a  living  organism, 
—  a  microorganism. 

Ger'mi-cide  (germ  and  Lat.  caedere, 
to  kill).  An  agent  which  destroys 
germs,  especially  bacteria. 

Gland  (Lat.  glans,  an  acorn).  An 
organ  consisting  of  one  or  more 
follicles  and  ducts,  with  numer- 
ous blood  vessels  interwoven. 

GlOt'tis  (Gr.  7\wrra,  the  tongue). 
The  space  between  the  vocal 
cords. 

Glu'cose'  (Gr.  y\vi<fa,  sweet).  A  kind 
of  sugar  found  in  fruits,  also 
known  as  grape  sugar. 

Gly'co-gen  (Gr.  y\vi<fa,  sweet,  and 
-yeviris,  producing).  A  substance 
belonging  to  the  carbohydrates, 
found  especially  in  the  liver ;  also 
known  as  animal  starch. 

Hem'i-sphere  (Gr.  ^/-u-,  half,  and 
<r<paipa,  a  sphere).  Half  a  sphere  ; 
the  lateral  halves  of  the  cerebrum. 

Hem'or-rhage  (Gr.  afyea,  blood,  and 
prjyvfoai,  to  burst).  Bleeding,  or 
the  loss  of  blood. 

He-pat'ic  (Gr.  rjirap,  the  livef).  Per- 
taining to  the  liver. 

He-red'i-ty  (Lat.  hereditas,  heir- 
ship).  The  predisposition  or  ten- 
dency derived  from  one's  ancestors 
to  definite  physiological  actions 
or  anatomical  peculiarities. 


GLOSSARY   OF   TECHNICAL   TERMS 


337 


Hu'mor  (Lat.  ^#w0r,  moisture).  The 
transparent  contents  of  the  eye- 
ball. 

Hy'a-line  (Gr.  vaXos,  glass).  Glass- 
like,  resembling  glass  in  trans- 
parency. 

Hy'dro-gen.  An  elementary  gaseous 
substance,  which,  in  combination 
with  oxygen,  produces  water. 

Hy'dro-pho'bi-a  (Gr.  u5wp,  water, 
and  06/3os,  fear).  A  disease  caused 
by  the  bite  of  a  rabid  dog  or 
other  animal. 

Im-mune'  (Lat.  immunis,  exempt). 
Exempt  from  certain  diseases  by 
inoculation,  by  previous  attack, 
or  by  nature. 

In-ci'sor  (Lat.  inddere,  to  cut  into). 
Applied  to  the  four  front  teeth 
of  both  jaws,  which  have  sharp, 
cutting  edges. 

In'cus  (Lat.  incus,  an  anvil).  One 
of  the  bones  of  the  middle  ear. 

In'di-an  hemp.  The  common  name 
of  Cannabis  indica,  an  intoxicat- 
ing drug  known  as  "hasheesh" 
and  by  other  names  in  Eastern 
countries. 

In-fec'tion  (Lat.  inficere,  to  stain). 
The  communication  of  disease 
from  one  body  to  another,  or 
from  one  part  to  another  part  of 
the  same  individual  (auto-infec- 
tion). The  material  conveying  the 
disease ;  the  disease-producing 
agent. 

In-fe'ri-or  ve'na  ca'va  (Lat.).  The 
vein  carrying  blood  from  the  lower 
part  of  the  body  into  the  heart. 


In'flam-ma'tion  (Lat.  in,  in,  and 
ftamma,  a  flame).  Tissue  changes 
accompanied  with  redness  or 
swelling  of  any  part  of  the  body, 
with  heat  and  pain. 

In-oc'u-la'tion  (Lat.  inoculare,  to 
ingraft).  The  introduction  of 
the  germs  of  disease,  generally 
through  the  skin,  so  as  to  pro- 
duce the  disease. 

rris  (Gr.  I/HS,  the  rainbow).  The  thin 
muscular  ring  which  lies  between 
the  cornea  and  crystalline  lens, 
giving  the  eye  its  special  color. 

Jaun'dice  (Fr.  jaune,  yellow).  A 
disorder  in  which  the  skin,  eyes, 
mucous  membranes,  and  secre- 
tions assume  a  yellowish  tint,  due 
to  the  presence  of  bile  pigments 
in  the  blood. 

Lab'y-rinth  (Gr.  \aptpiv0os,  a 
maze).  The  internal  ear,  so 
named  from  its  many  windings. 

Lach'ry-mal  ap'pa-ra'tus  (Lat.  la- 
crima,  a  tear).  The  organs  for 
forming  and  carrying  away  the 
tears. 

Lens  (Lat.  lens,  a  lentil).  A  piece 
of  transparent  glass  or  other  sub- 
stance so  shaped  as  either  to  con- 
verge or  disperse  the  rays  of  light. 

Lig'a-ture  (Lat.  ligare,  to  bind). 
A  thread  of  some  material  used 
in  tying  arteries  or  other  parts. 

Lobe  (Gr.  Xo/36s,  lobe  of  the  ear  or 
liver).  A  round,  projecting  part  of 
an  organ,  as  of  the  liver,  lungs,  or 
brain. 


338 


OUR   BODIES   AND    HOW   WE   LIVE 


Lockjaw,  see  "  Tetanus." 

Lymph  (Lat.  lympha,  pure  water). 

The  watery  fluid  in  the  lymphatic 

vessels. 

Marie-us  (Lat.  malleus,  a  hammer). 
The  mallet ;  one  of  the  small 
bones  of  the  middle  ear. 

Me-a'tus  (Lat.  mearc,  to  pass).  A 
natural  passage  or  canal. 

Me-duTla  ob-lon-ga'ta  (Lat.).  The 
"  oblong  marrow,"  also  called  the 
spinal  bulb ;  that  portion  of  the 
brain  which  lies  upon  the  basilar 
process  of  the  occipital  bone. 

Mei-bo'mi-an.  A  term  applied  to 
the  small  glands  between  the 
conjunctiva  and  tarsal  cartilages, 
discovered  by  Meibomius. 

Mem-bra'na  tym'pa-ni  (Lat.).  Lit- 
erally," the  drum  membrane  " ;  the 
membrane  separating  the  outer 
from  the  middle  ear. 

Mes'en-ter-y  (Gr.  /x&ros,  middle,  and 
evrepov,  the  intestine).  A  fold 
of  the  peritoneum,  surrounding 
an  intestine,  especially  the  small 
intestine. 

Mi'crobe  (Gr.  /j.iKp6s,  little,  and  /3/os, 
life).  A  living  organism  of  very 
small  size, — a  microorganism, — 
either  animal  or  vegetable. 

More-cule  (Lat.  molecula,  dim.  of 
moles,  a  mass).  The  smallest  por- 
tion of  a  substance  which  can  retain 
the  properties  of  the  substance. 

Mo'tor  (Lat.  movere,  to  move).  The 
name  of  the  nerves  which  con- 
duct to  the  muscles  the  stimulus 
which  causes  them  to  contract. 


Mu'cous  mem'brane.  The  thin  layer 
of  tissue  which  covers  those  inter- 
nal cavities  or  passages  which  com- 
municate with  the  external  air. 

Mu'cus  (Lat.).  The  thin  glairy  fluid 
secreted  by  mucous  membranes. 

Nar-cot'ic  (Gr.  vapKovv,  to  benumb). 
A  substance  that  produces  stu- 
por, convulsions,  and  sometimes 
death. 

Nic'o-tine  (from  Jean  Nicot,  who 
introduced  tobacco  into  France). 
A  poisonous  substance  found  in 
the  leaves  of  the  tobacco  plant. 

Nu-cle'o-lus  (Lat.  dim.  of  nucleus}. 
A  small  body  often  found  within 
the  nucleus  of  a  cell. 

Nu'cle-US  (Lat.  nucleus,  kernel).  An 
essential  part  of  a  typical  cell, 
often  spherical  and  usually  found 
near  the  center. 

(E-soph'a-gUS  (Gr.  Qtyeiv,  ofaciv,  to 
carry,  and  (fiaye'iv,  to  eat).  The 
tube  leading  from  the  throat  to 
the  stomach  ;  the  gullet. 

Ox-i-da'tion.  The  union  of  oxygen 
with  other  substances,  as  in  com- 
bustion. The  essential  part  of 
burning  and  of  breathing. 

Palate  (Lat.  palatum,  the  palate). 
The  roof  of  the  mouth,  forming 
the  hard  palate,  and  the  curtain 
at  the  back  of  the  mouth,  called 
the  soft  palate. 

Pal'pi-ta'tion  (Lat.  palpitarc,  to 
throb).  A  violent  and  irregular 
beating  of  the  heart. 


GLOSSARY  OF  TECHNICAL  TERMS 


339 


Pa-pil'lae  (Lat.  papilla,  a  nipple). 
The  small  elevations  found  on 
the  skin  and  mucous  membranes. 

Pa-rary-sis  (Gr.  wapd,  beside,  and 
XiW,  to  loosen) .  Loss  of  function, 
especially  of  motion  or  feeling. 

Par'a-site  (Gr.  wapd,  beside,  and 
(Tiros,  food).  A  plant  or  animal 
living  upon  or  within  another 
organism,  called  the  host. 

Pel' vis  (Lat.  pelvis,  a  basin).  The 
bony  cavity  at  the  lower  part  of 
the  trunk. 

Pep'sin  (Gr.  TT^IS,  digestion).  A 
ferment  found  in  the  gastric  juice, 
and  capable  of  digesting  proteids 
in  the  presence  of  an  acid. 

Pep'tone  (Gr.  irtirTeiv,  to  digest).  A 
proteid  body  formed  by  the  action 
of  ferments  on  albumins  or  other 
proteids  during  gastric  and  pan- 
creatic digestion. 

Per'i-car'di-um  (Gr.  irept,  about,  and 
KapSla,  heart).  The  sac  inclosing 
the  heart. 

Per'i-os 'te-um  (Gr.  irepi,  around, 
and  6ffT^ov,  a  bone).  A  delicate 
membrane,  which  invests  and 
nourishes  the  bones. 

Per'i-tO-ne'um  (Gr.  irepirdveiv,  to 
stretch  around).  The  investing 
membrane  of  the  stomach,  intes- 
tines, and  other  abdominal  organs. 

Pha-lan'ges  (Gr.  <f)d\ay£,  a  body  of 
soldiers  closely  arranged  in  ranks 
and  files).  The  bones  of  the 
fingers  and  toes. 

Phar'ynx  (Gr.  <f)dpvy%,  the  throat). 
The  cavity  behind  the  mouth  and 
the  nose,  leading  to  the  gullet. 


Pi'a  ma'ter  (Lat.  pia  mater,  gentle 
mother).  The  innermost  of  the 
three  coverings  of  the  brain.  It  is 
thin  and  delicate ;  hence  the  name. 

Pin'na  (Lat.  pinna,  a  wing).  The 
external  cartilaginous  flap  of  the 
ear. 

Plas'ma  (Gr.  ir\d<r<Teiv,  to  mold). 
The  fluid  part  of  the  blood  and 
the  lymph. 

Pleu'ra  (Gr.  Tr\evpd,  a  rib,  the  side). 
A  membrane  covering  the  lung 
and  lining  the  chest. 

Plex'us  (Lat.  plectere,  to  braid).  A 
network  of  vessels,  nerves,  or 
fibers. 

Pneu'mo-gas'tric  (Gr.  •jrveijfj.uv,  the 
lungs,  and  yaar-fip,  the  stomach). 
The  longest  of  the  cranial  nerves 
giving  off  branches  to  the  lungs, 
the  heart,  the  alimentary  canal, 
and  other  parts ;  also  called  the 
vagtis,  or  wandering  nerve. 

Poi'son  (Lat.  potio,  a  draught).  A 
substance  that,  when  introduced 
into  the  body,  either  destroys  life 
or  impairs  seriously  the  function 
of  one  or  more  of  its  organs. 

Por'tal  vein  (Lat.  porta,  a  gate). 
The  venous  trunk  formed  by  the 
veins  coming  from  the  stomach 
and  the  intestines.  It  carries  the 
blood  to  the  liver. 

Proc'ess  (Lat.  pro,  forth,  and  cedere, 
to  go).  Any  projection  from  a 
surface ;  also,  a  method  of  per- 
formance, a  procedure. 

Pro'te-ids  (Gr.  Trpwros,  first).  A 
general  term  for  the  albuminous 
constituents  of  the  body. 


340 


OUR   BODIES   AND   HOW  WE   LIVE 


Pro'to-plasm  (Gr.  TrptDros,  first,  and 
ir\a(r<reiv,  to  mold).  The  viscid 
material  constituting  the  essential 
substance  of  living  cells  upon 
•'which  all  the  vital  functions  of 
the  body  depend. 

Pto'ma-ine  (Gr.  TrrtD/^a,  a  corpse). 
One  of  a  class  of  substances,  re- 
sembling the  vegetable  alkaloids, 
formed  during  the  decomposition 
of  proteids.  See  "  Toxin." 

Pty'a-lin  (Gr.  imjaXov,  saliva).  A 
ferment  in  saliva,  having  power 
to  convert  starch  into  sugar. 

Pu'pil  (Lat.  pupilla).  The  central, 
round  opening  in  the  iris,  through 
which  light  passes  into  the  inte- 
rior of  the  eye. 

Pus  (Lat.).  A  yellowish -white, 
creamy  liquid  produced  by  sup- 
puration. It  consists  mostly  of 
cells  floating  in  a  liquid. 

Py-ae'mi-a  (Gr.  irfov,  pus,  and  af/*a, 
blood).  A  form  of  blood  poison- 
ing produced  by  the  absorption 
into  the  blood  of  morbid  matters 
usually  originating  in  a  wound  or 
local  inflammation. 

Py-lo'rus  (Gr.  Trv\wp6s,  a  gate 
keeper).  The  opening  of  the 
stomach  at  the  beginning  of  the 
small  intestine. 

Re'flex  (Lat.  reflectere,  to  bend  back). 
Involuntary  movements  or  secre- 
tion produced  by  an  excitation 
traveling  along  a  sensory  nerve 
to  a  center,  where  it  is  turned 
back  or  reflected  along  motor  or 
secretory  nerves. 


Res'pi-ra'tion  (Lat.  re-,  again,  and 
spirare,  to  breathe).  The  act  of 
breathing  in  and  breathing  out  air. 

Ret'i-na  (Lat.  rete,  a  net).  The 
innermost  of  the  three  tunics,  or 
coats,  of  the  eyeball,  being  an 
expansion  of  the  optic  nerve. 

Ri'ma  glot'ti-dis  (Lat.  rima,  a  chink 
or  cleft).  The  opening  of  the 
glottis. 

Roent'gen  rays.    See  "  X-rays." 

Sar'co-lem'ma  (Gr.  <rdp£,  flesh,  and 
X^u/ua,  a  husk).  The  membrane 
which  surrounds  the  contractile 
substance  of  a  striped  muscular 
fiber. 

Scle-rot'ic  (Gr.  (TK\r]povv,  to  harden). 
The  tough,  fibrous  outer  coat  of 
the  eyeball. 

Se-ba'ceous  (Lat.  sebum,  tallow). 
Resembling  fat ;  the  name  of  the 
oily  secretion  by  which  the  skin 
is  kept  flexible  and  soft. 

Se-cre'tion  (Lat.  secernere,  to  sepa- 
rate). The  process  of  separating 
from  the  blood  some  essential, 
important  fluid,  which  fluid  is  also 
called  a  secretion. 

Sem'i-cir'cu-lar  ca-nals'.  Three 
canals  in  the  internal  ear. 

Sep'ti-cse'mi-a  (Gr.  o-rj-n-Ti^s,  putre- 
fying, and  alfj.a,  blood).  Blood 
poisoning;  a  form  of  poisoning 
resulting  from  the  presence  in  the 
blood  of  the  products  of  putre- 
factive microorganisms. 

Se'ruin  (Lat.  serum,  whey).  The 
clear,  watery  fluid  wThich  separates 
from  the  clot  of  the  blood. 


GLOSSARY  OF  TECHNICAL  TERMS 


341 


Spu'tum,  pi.  §puta  (Lat.  spuere,  to 
spit).  Matter  which  is  coughed 
up  from  the  air  passages. 

Sta'pes  (Lat.  stapes,  a  stirrup).  One 
of  the  small  bones  of  the  middle 
ear. 

Ster'il-i-za'tion  (Lat.  sterilis,  bar- 
ren). The  destruction  of  micro- 
organisms, especially  by  heat. 
Commonly  applied  to  the  prepa- 
ration of  milk  for  infants,  and  to 
surgical  dressings. 


An  agent  which  causes  an  increase 
of  activity  in  the  body  or  in  any 
of  its  parts  without  increasing  its 
supply  of  energy. 

Styptics  (Gr.  <rri;7rTi/c6s,  astringent). 
Substances  that  applied  locally 
arrest  bleeding. 

Sub-cla'vi-an  vein  (Lat.  sub,  under, 
and  clavis,  a  key).  A  great  vein, 
so  called  because  it  is  situated 
underneath  the  clavicle,  or  collar 
bone. 

Su-pe'ri-or  ve'na  ca'va  (Lat.).  The 
great  vein  of  the  upper  part  of 
the  body. 

Syn-o'vi-a  (Gr.  afo,  with,  and  Lat. 
ovum,  an  egg;  a  word  coined  by 
Paracelsus).  The  fluid  secreted 
by  the  synovial  membranes,  which 
lubricates  the  joints;  joint  oil.  It 
resembles  the  white  of  a  raw  egg. 

Tem'po-ral  (Lat.  tempera,  the  tem- 
ples). Pertaining  to  the  temples. 

Tet'a-nus  (Gr.  relveiv,  to  stretch). 
A  disease  marked  by  persistent 
contractions  of  all  or  some  of  the 


voluntary  muscles ;  those  of  the 
jaw  are  sometimes  solely  affected ; 
it  is  then  termed  lockjaw. 

Thy'roid  (Gr.  6vpe6s,  a  shield,  and 
e[5os,  form).  The  largest  of  the 
cartilages  of  the  larynx;  its  pro- 
jection in  front  is  called  "  Adam's 
apple." 

Tis'sue  (Fr.  tissu,  from  Lat.  texere, 
to  weave).  Any  substance  or 
texture  in  the  body  formed  of 
various  elements,  such  as  cells, 
fibers,  blood  vessels,  etc.,  inter- 
woven with  each  other. 

To-bac'co  (Indian  tabaco,  the  tube, 
or  pipe,  in  which  the  Indians 
smoked  the  plant).  A  narcotic 
plant  used  for  smoking  and  chew- 
ing, and  in  snuff. 

Tox'in  (Gr.  To£t/c6i>,  poison).  A 
poison  formed  by  bacteria  in 
both  living  tissues  and  dead  sub- 
stances ;  a  poisonous  ptomaine. 

Tra'gus  (Gr.  rpdyos,  a  goat).  The 
eminence  in  front  of  the  opening 
of  the  ear ;  sometimes  hairy,  like 
a  goat's  beard. 

Tryp'sin  (Gr.  rptyis,  a  rubbing). 
The  ferment  principle  in  pancre- 
atic juice  which  converts  proteid 
material  into  peptones. 

Tu'ber-cle  (Lat.  tuberculum,  dim.  of 
tuber,  a  hump).  A  pimple,  swell- 
ing, or  tumor;  the  specific  lesion 
produced  by  the  tubercle  bacillus. 

Tu-ber/cu-lo'sis  (same  derivation  as 
"  tubercle  ").  An  infectious  dis- 
ease due  to  the  bacillus  tuber- 
culosis. The  form  of  this  disease 
with  marked  pulmonary  symptoms 


342 


OUR  BODIES   AND   HOW  WE   LIVE 


is  popularly  known  as  consump- 
tion. 

Tur'bi-na'ted  (Lat.  turbo,  a  top). 
Formed  like  a  top ;  a  name  given 
to  the  bones  in  the  outer  walls  of 
the  nasal  fossae. 

Tym'pa-num  (Gr.  r^iravov,  a  drum). 
The  cavity  of  the  middle  ear, 
resembling  a  drum  in  being  closed 
by  two  membranes. 

U're-a  (Gr.  o$pov,  urine).  Chief  solid 
constituent  of  urine ;  nitrogenous 
product  of  tissue  decomposition. 

U-re'ter  (Gr.).  The  tube  through 
which  the  urine  is  conveyed  from 
the  kidneys  to  the  bladder. 

U'vu-la  (Lat.  dim.  of  uva,  a  grape, 
a  bunch  of  grapes).  The  small 
pendulous  body  at  the  middle  of 
the  soft  palate. 

Vac'cine  vi'rus  (Lat.  vacca,  a  cow). 
The  virus  used  in  performing  vac- 
cination ;  now  usually  derived 
directly  from  the  cow. 

Var'i-cose  (Lat.  varix,  a  dilated 
vein).  Distended  or  enlarged,  as 
a  vein. 

Vas'cu-lar  (Lat.  vasculum,  dim.  of 
vas,  a  vessel).  Pertaining  to  or 
possessing  blood  or  lymph  vessels. 

Ve'nae  ca'vae  (Lat.  pi.  of  -vena  cava, 
hollow  vein).  A  name  given  to 
the  two  great  veins  which  meet 
at  the  right  auricle  of  the  heart. 

Ven'ti-la'tion  (Lat.  ventilare,  to 
fan).  The  process  of  replacing 
the  foul  or  vitiated  air  in  any 


room  or  confined  space  with  air 
that  is  pure. 

Ver'mi-fonn  (Lat.  vermis,  a  worm, 
a.nd/orma,  form).  Worm-shaped. 

Ves'ti-bule  (Lat.  vestibulum,  a  fore- 
court). A  portion  of  the  internal 
ear,  communicating  with  the  semi- 
circular canals  and  the  cochlea. 

Vil'li  (Lat.  villus,  shaggy  hair). 
Minute  threadlike  projections 
upon  the  internal  surface  of  the 
small  intestine. 

Vi'rus  (Lat.  vtrus,  poison).  The 
poison  of  an  infectious  disease, 
especially  one  found  in  the  secre- 
tions or  tissues  of  an  individual 
or  animal  suffering  from  an  infec- 
tious disease. 

Vit're-ous  (Lat.  vitrum,  glass). 
Having  the  appearance  of  glass ; 
applied  to  the  humor  occupying 
the  largest  part  of  the  cavity  of 
the  eyeball. 

Viv'i-sec'tion  (Lat.  vivus,  alive,  and 
secare,  to  cut).  Dissection  of  a 
living  animal ;  experimentation 
upon  an  animal  while  still  alive. 

Weal  cords.  Two  elastic  bands  or 
transverse  folds  of  the  larynx. 

X-rays,  or  Roent'gen  rays.  The 
peculiar  ether  rays  or  waves  dis- 
covered by  Roentgen  in  1895. 
These  rays  penetrate  substances 
like  wood,  the  bodily  tissues,  and 
many  other  substances  which  are 
opaque  to  the  light  of  the  sun ; 
extensively  used  in  the  diagnosis 
of  surgical  cases. 


INDEX 


Absorption  .     .     .     .     .     .     .  117 

by  lacteals 117 

by  lymphatics      .     .     .     .  119 

by  blood  vessels      .     .     .  1 20 

Accidents  and  emergencies     .  280 

Acetabulum 29 

Achilles,  Tendon  of  ....  34 

Adam's  apple 275 

Air,  Composition  of  .     .     .     .  170 

how  changed  by  breathing  1 70 

Impurities  in 173 

Bacteria  carried  by .     .     .  174 

Air  passages 161 

Protection  of 165 

Air  sacs 163 

Albuminoids 70 

Alcohol,  Effect  of,  on  bones  .  40 
Effect  of,  on  muscular 

strength 62 

and  army  operations    .     .  64 

as  a  poison 94 

habit 96 

not  a  food 97 

Oxidation  of 97 

Effect  of,  on  mucous  mem- 
branes       127 

Effect  of,  on  stomach  .  127,  128 
Effect  of,  on  gastric  diges- 
tion      128 

Effect  of,  on  liver    .     .     .  131 


Alcohol,  Effect  of,  on  blood  .  155 

Effect  of,  on  blood  vessels  1 56 

Effect  of,  on  heart  .     .  157,  158 

Effect  of,  on  lungs  .     .     .  1 80 
Effect   of,   on    breathing 

capacity 180 

Effect  of,  on  bodily  heat .  181 
Effect  of,   on  pulmonary 

diseases 181 

Effect    of,   on   endurance 

of  heat  and  cold  .     .     .  182 

Effect  of,  on  skin    .     .     .  208 

Effect  of,  on  kidneys  .     .  209 
Effect     of,     on     nervous 

system 231 

Self-control  weakened  by  233 

Effect  of,  on  character     .  235 

Final  effect  of     ....  236 

Moral  effect  of    ....  236 

results,  Hereditary,  of      .  237 

Effect  of,  on  hearing  .     .  258 

Effect  of,  on  sight  .     .     .  271 

Effect  of,  on  voice  .     .     .  278 

Alcoholic  liquors  in  navy   .     .  65 

fermentation 85 

beverages 86-93 

habit,  Effect  of  ....  236 

Alimentary  canal 100 

Amffiba,  Cell  life  of  ....  7 

Anatomy  defined  .     .     .     .     .  14 


343 


344 


OUR   BODIES   AND   HOW  WE   LIVE 


Antidotes  for  poisons     .     .300-303       Blood I33~I38 

Antitoxin  treatment  of  disease  312  Corpuscles  of     .     .     .133,134 

Aorta  and  its  branches  .     .     .  145               Uses  of 133 

Apparatus,  Question  of        327,328               Properties  of 133 

Appendicitis 121                Clotting  of 136 

Areolar  tissue 12  Importance  of,  clotting    .  138 

Arteries    .........  145  Blood  vessels,  connected  with 

Asphyxia 295                   heart 144-146 

Atmosphere,  how  made  impure  174  Effect  of  alcohol  on     .     .  156 

Auditory  nerve 255               Injuries  to 290 

Bone,  how  made  up  ....  16 

Backbone 26  Microscopic  structure  of .  20 

Bacteria,    Importance    of,    in  Bones,  General  structure  of    .  18 

nature 81               Shape  of 19 

as  causes  of  disease     .     .  82               how  joined 34 

as   active   agents   in   fer-                         how  fastened 36 

mentation 83               Uses  of 37 

Work  done  by    ....  305  broken,  Repair  of   ...  38 

Nature  of 305               Health  of 39 

Importance  of     ....  306  Growth  of,  how  modified  39,  40 

Disease-producing  .     .     .  307  Effect  of  alcohol  on     .     .  40 

in  food 307  Effect  of  tobacco  on    .  41 

Access  of,  to  body  .     .     .  308               Table  of 42 

Behavior  of,  in  body   .     .  310               Broken 293 

Warfare   between,   and  Bowels,  proper  care  of  .     .     .  126 

cells 312       Brain 215 

Bathing,  Hints  on      ....  199               Weight  of 215 

Baths,  and  bathing    ....  199                Parts  of 216 

Cold 199  Membranes  of     .     .     .     .  218 

Beer 88  Reflex  action  and    .    .  222,  225 

Food  value  of     ....  89  Effects  of  alcohol  on  .     .  232 

Drinking,  in  place  of  ar-  Bread,  Different  kinds  of  .     .  74 

dent  spirits      ....  90       Breathing 161-183 

Bicycle,  Use  of 58               Object  of 161 

Bile 114  Movements  of     ....  167 

as  a  help  in  digestion  .     .  114  See  also  under  Respira- 

Bleeding,  from  nose  ....  287  tion 

How  to  stop  ....  291-293       Bronchial  tubes 163 

Blind  spot 264       Burns  or  scalds 283 


INDEX 


345 


PAGES 

Caecum 114 

Canaliculi 20 

Capillaries 147 

Carbohydrates 6,  71 

Carpal  bones 31 

Cartilage •    .  13 

Thyroid 275 

Cricoid 275 

Cell  life  shown  by  amoeba  .     .  7 

Cells 6 

Variety    of     work     done 

by 7 

Epithelial 10 

Nerve 212,  213 

Cerebellum 218 

Functions  of 218 

Cerebrum 216 

Convolutions  of.     .     .     .  217 

Chemical  elements  in  the  body  4 

Chloral  and  chloral  habit   .     .  243 

Choroid  coat     ......  260 

Chyle 117 

Chyme 112 

Cider 91 

Cigarettes 131,  239 

Cilia  of  air  passages  ....  165 

Ciliary  muscle 263 

Circulation,  compared  to  water 

service 139 

General  plan  of  .     .     .     .  139 

General  course  of    .     .     .  148 

Pulmonary 148 

Systemic 150 

Portal 151 

Effect  of  alcohol  on     .     .  1 56 

Clavicle 30 

Clothing,  Dangers  from 

change  of 200 

Hints  on  use  of .     .     .     .  201 


Clothing,  Advice  on  use  of     .  201 
Additional  hints  on   use 

of 202 

Catching,  on  fire     .     .     .  283 

Clotting  of  blood 136 

Coccyx 27 

Cochlea 254 

Coffee 78 

Cold  and  heat,  Sensations  of .  248 

Collar  bone 30 

Colon 114 

Color  blindness 267 

Condiments 74 

Conjunctiva 265 

Connective  tissues     ....  1 1 

with  elastic  fibers    ...  12 

with  white  fibers     ...  12 

Consumption 175,  315 

Contagion 308 

Contraction,  muscular,  Object 

of 47 

Contusions  and  bruises .     .     .  289 

Cooking 78 

Cornea 260 

Corpuscles,  Blood     ....  134 

Red  .........  134 

White 136 

Touch 187 

Cranial  nerves 220 

Cranium,  Bones  of    ....  21 

Cricoid  cartilage 275 

Crystalline  lens 261 

Work  done  by    ....  262 

Cuticle 185 

Deglutition 108 

Dermis,  or  true  skin  .     .     .     .  187 

Diaphragm 168 

Diet,  Important  articles  of      .  74 


346 


OUR   BODIES   AND    HOW   WE    LIVE 


Digestion,  Organs  of  and  ob- 
ject of 100 

in  small  intestine     .     .  114-120 

in  large  intestine      .     .     .  121 

Effect  of  alcohol  on     .  127-131 

Diphtheria    .     .     ....     .     •  316 

Disease,  Means  to  avert  dan- 
ger from      .     .     .....  312 

Diseases,  infectious  and  con- 
tagious, Management 
of.  .  .  3i5-3i7»32i-323 

Nurses  in 321 

Hints  on  nursing     .     .     .  322 

Disinfectants,  Air  and  water  as  312 

Common 314 

Disinfection 314 

Distillation,  Process  of  ...  92 

Distilled  liquors 93 

Dog  bites 285 

Drinking,  social,  Danger  of     .  96 

Drinks,  Refreshing    ....  77 
Drowning,   apparent,  Method 

of  treating  ....  296,  297 

Drugs,  Dangerous      ....  244 

Drugs  and  narcotics  ....  244 

Duct,  Common  bile     .     .  114 

Thoracic    .     .     .     ...  118 

Tear ,     .  266 

Duodenum 114 

Ear,  Outer 252 

Middle 253 

Bones  of 253 

Inner 254 

Hints  on  care  of      ...  256 

Suggestions  on  care  of     .  257 

Foreign  bodies  in    ...  288 

Eggs  as  food 75 

Elements,  Chemical,  in  the  body  4 


PAGES 

Emetics 299 

Epidermis,  or  cuticle      .     .     .  185 
Epiglottis      .     .     108,  162,  273,  275 

Epileptic  fits 282 

Epithelium 10 

Ciliated 10 

Ethmoid  bone 22 

Eustachian  tube 254 

Excretion 107 

Chief  organs  of  ....  204 

Exercise,  Physical      ....  53 

Need  of 53 

Effect  of,  on  muscles  .     .  54 
Effect     of,     on     various 

organs     ......  54 

Amount  of,  required    .     .  55 

Time  for 56 

Different  kinds  of  ...  57 

Gymnastic 58 

Vigorous 58 

Physical,  in  schools      .     .  59 
Beneficial    effect    of,    in 

schools 60 

Effect  of  alcohol  and  to- 
bacco on  capacity  for    60-66 
Experimental  work   in   physi- 
ology         328 

Expiration 167,  1 68 

Eye 258 

Coats  of 259 

Refractive  media  of     .     .  262 

Muscles  of 264 

how  abused 269 

Hints  on  care  of      ...  270 

Rest  for 270 

Effects    of    tobacco    and 

alcohol  on 271 

Foreign  bodies  in    ...  288 

Eyeball 258 


INDEX 


347 


Eyelashes  and  eyebrows 

Eyelids 265 

Eyesight,    Good    and   proper 

light  essential  to  good  . 

Expiration 

Face,  Bones  of  the  .  .  .  . 

Fainting 

Fatty  tissue 

Fats  and  oils 

Femur 

Fermentation,  Alcoholic  .  81 

Nature  of 

Different  forms  of  ... 

Changes  wrought  by  .  . 

Fibula 

Fits,  Epileptic  and  hysterical . 

Fontanelles 

Food  tube 

Food,  why  we  need  it  ... 

Waste  made  good  by  .     . 

how  swallowed    .... 

how  absorbed      .... 

Quantity  of 

How  much,  to  eat  .     .     . 

Ill  effects  of  eating  too 
much 

What  to  use  as  .... 

When  to  eat 

Time  to  eat 

Hints  about  eating .  .  . 
Foods,  Classification  of  .  . 

Nitrogenous 

Proteid 

Starches  and  sugars     .     . 

Fats  and  oils 

Mineral  salts 

Mineral 

Foot 


A.GES 

PAGES 

265 

•            30 

265 

Fractures,  Different  kinds  of 

38 

Frontal  bone      •  , 

22 

269 

Frostbites     , 

,       285 

1  68 

Fruits  as  food  

74 

22 

Gallbladder      

114 

282 

Gases,  Diffusion  of    .     .     .     , 

,     172 

6 

Exchange  of  

172 

72 

Gastric  glands  , 

IIO 

33 

Gastric  juice     , 

ii  i 

>85 

Action  of  

112 

81 

Germs  , 

83 

84 

Glands      

.       101 

86 

Salivary      , 

IO4 

33 

Gastric  , 

I  IO 

282 

Lymphatic      .     .     .  '  .     , 

1  20 

24 

Ductless     

.       120 

100 

Suprarenal      

I  2O 

69 

Thymus      

,       120 

69 

Thyroid      , 

1  2O 

1  08 

Oil     

194 

117 

Sweat    

195 

122 

Glottis      , 

276 

122 

Glycogen      , 

114 

Gristle      

13 

122 

Gullet  

IO9 

I23 

Gymnastic  exercises  .     .     .     . 

58 

124 

I24 

Hair,  Structure  of      .     .     .     , 

190 

125 

Color  of     

I9I 

70 

Growth  of  .     .     .     .     .     . 

I9I 

70 

Muscles  of      

I9I 

70 

Care  of       

2OO 

71 

Hand  

3' 

72 

Haversian  canals  

20 

73 

Head,  Bones  of     

21 

75 

Hearing,  Sense  of      .     .     .     . 

251 

33 

Organ  of    .     .     .     .    '.     . 

252 

348 


OUR   BODIES   AND    HOW  WE    LIVE 


Hearing,  Mechanism  of       .     .  255 

Effect  of  narcotics  on  .     .  258 

Heart 140 

Chambers  of 141 

Valves  of 142 

Work  of 143 

Blood  vessels  connected 

with 144,  145 

Beat  of 153 

Sounds  of 153 

Effect  of  alcohol  on     .     .  157 

Effect  of  tobacco  on   .     .  1 58 

Heat  and  cold,  Sensations  of  248 

Heat,  Natural,  of  the  body     .  178 

how  produced     ....  179 

how  lost 179 

Hepatic  arteries  and  veins.     .  152 

Hip  bones 29 

Humerus 30 

Hygiene  defined 14 

Hyoid  bone 24 

Hysterics 282 

Ileum 114 

Infection,  pulmonary,  Dangers 

from 175,  315 

Influenza 315 

Inoculation 308 

Inspiration 167,  1 68 

Intestine,  Small 114 

Digestion  in  small  .     .     .  114 

Large 121 

Iris  and  pupil 260 

Jawbones,  Upper 23 

Jawbone,  Lower 23 

Jejunum 114 

Joints 34 

Different  kinds  of  ...  35 


PAGES 

Kidneys 203,  206 

Structure  of 206 

Work  done  by  ....  206 

Health  of 207 

Effect  of  alcohol  on  .  .  209 

Knot,  square,  How  to  tie  a     .  293 

Labyrinth 254 

Lachrymal  bones  .....  23 

apparatus 266 

Lacteals .  117 

Lacunas: 20 

Lamellae 20 

Larynx 275 

Leg,  Bones  of 33 

Lens,  Crystalline 261 

Ligaments 36 

Limbs,  Upper 29 

Lower 31,  32 

Liver 114 

Work  done  by    ....  114 

Glycogenic  function  of     .  114 

Effect  of  alcohol  on    .     .  131 

Locomotive,  Body  compared  to  3 

Long  or  far  sight 268 

Lungs,  Structure  of  .     .     .     .  164 

Effect  of  alcohol  on     .     .  180 

Bleeding  from     ....  293 

Lymph 148 

Lymphatics 117,  120 

Work  done  by    ....  119 

Malar  bones 22 

Malt    liquors,    Physiological 

effects  of     .     .          .     .  90 

Mastication 102 

Maxillary,  Superior   ....  23 

Inferior 23 

Meats  as  food 75 


INDEX 


349 


PAGES 

Medulla  oblongata     .     .     .     .  218 

Metacarpal  bones .     .....  31 

Metatarsal  bones 34 

Microbes 83 

Microorganisms 83 

Microscope,  Use  of  ....  328 

Milk  and  eggs 75 

Mineral  foods 75 

salts 73 

Mold 83 

Mouth 101 

Muscles,  as  organs  of  motion  .  44 

Kinds  of 45 

voluntary,  General  build 

of 46 

Involuntary 46 

how  they  contract  ...  47 

why  they  contract  ...  47 

how  they  work  in  harmony  48 

how  named 50 

of  head  and  neck    ...  51 

of  shoulders  and  chest     .  52 

of  back  and  legs      ...  53 

Effect  of  exercise  on  .     .  54 

Effect  of  alcohol  on    .     .  62 

Effect  of  tobacco  on   .     .  63 

Muscular  action,  Variety  of    .  44 

contraction 47 

sense 247 

Nails 192 

Care  of 193 

Narcotics 244 

Nasal  bones 23 

Near  sight 268 

Nerve  cells 212 

and  fibers,  Work  done  by  213 

Nerve  fibers 212 

Nerves,  Structure  of      ...  214 


PAGES 

Nerves,  Cranial 220 

Spinal 225 

Nervous  system,  General  view 

of 211,  214 

compared  to  telegraph 

system 211 

Divisions  of 214 

Health  of 228 

Effect  of  worry  on  .     .     .  228 

Abuse  of 229 

Effect  of  alcohol  on    .  231-237 
Effect  of  tobacco  on    .  238-241 

Nitrogenous  foods     ....  70 

Nose,  Bleeding  from  the    .     .  287 

Foreign  bodies  in    ...  287 

Nostrils 161 

Nurses  in  contagious  and  in- 
fectious diseases .     .     .  321 

Nursing,  Hints  on     ....  322 

Occipital  bone 22 

(Esophagus 109 

Opium,  Various  forms  of    .     .  242 

Poisonous  effects  of    .     .  242 

habit 242 

Caution  in  use  of    ...  243 

Poisonous  forms  of     .     .  302 

Organ  defined 14 

Organic  compounds  ....  5 

Three  classes  of      ...  5 

Palate  bones 23 

Pancreas 116 

Pancreatic  juice 116 

Papillae 247 

Parietal  bones 22 

Parotid  gland 106 

Patella 33 

Pelvis 29 


350 


OUR   BODIES  AND    HOW   WE   LIVE 


Pepsin in 

Peptones 112 

Pericardium 141 

Periosteum 20 

Perspiration 196 

Phalanges 31,  34 

Pharynx 273 

Physical  exercise  ....      53-60 

why  needed 53 

Effect  of,  on  muscles  .     .  54 

Amount  of 55 

Time  for 56 

Kinds  of 57 

Walking  for 57 

in  schools 59 

Effect  of,  in  schools    .     .  60 

Physiology,  in  schools    ...  i 

Importance  of  study  of    .  i 

defined 14 

Study  of,  in  schools     .  325-329 

Experimental  work  in  .     .  328 

Plants,  Poisonous 303 

Pleura .  164 

Pneumogastric  nerve      .     .     .  221 

Pneumonia 315 

Poison,  Definition  of      ...  93 

Alcohol  as  a  .     .     .     .     .  94 

Poisons,  Action  of     ....  93 

Careless  use  of  ....  298 

Kinds  of 300 

Acid 300 

Alkaline 301 

Metallic 301 

Vegetable  ......  303 

Antidotes  for      ...  300-303 

Portal  circulation 151 

Portal  vein 152 

Pressure,  Where  and  how  to 

apply,  to  stop  bleeding  291 


Proteids   ........ 

Protoplasm  ....... 

Nature  of  ...... 

Energy  set  free  by  ... 
Pulmonary  artery  ..... 

veins      ......  144, 

circulation  ...... 

infection    ...... 

Pulse   ......... 

Pupil  of  the  eye     ..... 

Pylorus  ........ 


144 
146 
148 
175 
153 
260 


Radius      ........  30 

Receptaculum  chyli  .     .     .     .  118 

Rectum    ........  114 

Reflex  action,  of  spinal  cord 

and  brain    .....  222 

Importance  of     ,     ...  223 

Examples  of  .....  224 

Relief  of,  to  brain  .     .     .  225 

Reflex  centers  in  the  brain      .  222 

Renal  secretion     .....  206 

Respiration,  Object  of  .     .     .  161 

Movements  of    .     .     .     .  167 

Mechanism  of     .     .     .     .  168 

Effect  of,  on  the  air    .     .  170 

Changes  of  air  in    .     .     .  171 

in  the  tissues.     .     .     .     .  173 

Effect  of  alcohol  on    .     .  180 

artificial,  Method  of     .     .  298 

Retina      ........  260 

Formation  of  image  on    .  263 

Ribs     .........  28 

Ringworm     .......  309 

Sacrum     ......     .     .  26 

Saliva,  Action  of  .....  106 

Salivary  glands      .....  104 

Salts  as  food     ......  73 


INDEX 


351 


PAGES 

Salts,  Inorganic     .....  6 

Scalds  and  burns 283 

Scapula 30 

Scarfskin.     .     .     .  '.  .  .     .     .  185 

Scarlet  fever 316 

Sclerotic  coat 259 

Secretion 107 

Semicircular  canals    .     .     .     .  254 

Semilunar  valves 143 

Sensation 246 

Sensations,  General  ....  246 

Senses,  Special 247 

Sick  room,  Care  of    ...  31*7-324 

Location  of 318 

Fresh  air  and  light  in  .     .  318 

Hints  for  care  of     ...  320 

Other  suggestions  for .     .  321 

Shoulder  blade 30 

Sight,  Sense  of 258 

Skeleton 16 

Review  analysis  of  ...  42 

Skin,  Structure  of      ....  185 

Two  layers  of     ....  185 

Color  of 1 86 

and  sense  of  touch       .     .  187 

Reasons  for  care  of     .     .  198 

Absorbent  powers  of  .  188,  190 

Effect  of  alcohol  upon     .  208 

Skull 21 

Sutures  of 24 

Sleep,  Importance  of     ...  230 

Hints  about    ....  230,  231 

Smell,  Sense  of 250 

Special  senses 246 

Speech 277 

Sphenoid  bone 22 

Spinal  cord 221 

Reflex  action  of .     .     .     .  222 

Spinal  nerves 225 


Spine .  26 

Wonders  of 27 

Spleen      . 120 

Sprains 294 

Starches  and  sugars  ....  71 

Sternum 28 

Stings  of  insects 287 

St.  Martin,  Alexis,  Case  of     .  129 

Stomach no 

Coats  of no 

Digestion  in in 

Sublingual  gland 106 

Submaxillary  gland    .     .     .     .  106 

Suffocation 295 

Sunstroke 283 

Suprarenal  glands      ....  120 

Sutures  of  skull 24 

Sweat 196,  197 

glands 195 

Sympathetic  system  ....  226 

Action  of 227 

Synovial  fluid 35 

Tarsal  bones 33 

Taste,  Sense  of 249 

Tea  and  coffee       .....  78 

Tear  gland  and  tear  passages  266 

Tears 266 

Teeth 102 

Structure  and  kinds  of     .  103 

Care  of 126 

Temperature,  Bodily      .     .     .  179 

Skin  as  a  regulator  of .     .  198 

Sense  of 247 

Temporal  bones 22 

Tendon  of  Achilles    ....  34 

Tendons 48 

Thigh  bone 33 

Thoracic  duct  .  118 


352 


OUR  BODIES   AND   HOW   WE   LIVE 


PAGES 

Throat 273 

Care  of 274 

Effect  of  alcohol  and  to- 
bacco on 278 

Foreign  bodies  in   ...  287 

Thymus  gland 120 

Thyroid  gland 1 20 

cartilage 275 

Tibia 33 

Tissue,  White  fibrous    ...  12 

Yellow  elastic     ....  12 

Areolar 12 

Fatty 13 

Tissues,  Epithelial     ....  10 

Connective n 

Tobacco,  Effect  of,  on  bones  .  41 

Effect  of,  on  muscles   .     .  63 
Effect     of,     on    physical 

development   ....  66 
Effect  of,  on  digestion     .  131 
Effect  of,  on  heart  .     .     .,159 
Effect  of,  on  nerve  cen- 
ters      238 

Effect  of,  on  nerves     .     .  239 
Effect  of,  on  young  people  240 
Effect  of,  on  mental  de- 
velopment    241 


Effect  of,  on  hearing  .  . 
Effect  of,  on  sight  .  .  . 
Effect  of,  on  throat  and 

voice 

Effect  of,  on  respiratory 


258 
271 

278 


Tongue,  as  organ  of  taste  . 
Touch,  Sense  of    .... 

corpuscles 187,  247 

Trachea    .  162 


278 
249 

247 


Trunk,  Bones  of 25 

Turbinated  bones 24 

Tympanic  membrane      .     .     .  253 

Tympanum 253 

Typhoid  fever 317 

Ulna 30 

Urine 206 

Vaccination 190,  313 

Valve,  Mitral 142 

Tricuspid 142 

Values,  of  the  heart  ....  142 

Semilunar 143 

Vegetables  and  fruits  ...  74 

Veins,  Pulmonary  .  .  .  .  146 

Ventilation 175 

how  secured 176 

of  schoolrooms  ....  177 

of  sick  room 318 

Vermiform  appendix  .  .  .  121 

Vision,  Common  defects  of  267,  268 

Effect  of  tobacco  on  .  .  271 

Vocal  cords 276 

Voice,  Production  of  ...  276 

Effect  of  narcotics  on  .  .  278 

Vomer  ........  24 


Walking 57 

Waste  matters,  Principal  .  .  203 

described 204 

Water,  as  food 76 

Use  of,  in  body  ....  77 

Windpipe 162 

Wine,  and  Danger  from  .  86,  87 

Yeast 85 


Date  Due 


MAR    2 :.  1932 


-jot-* 


LIBRARY 

COLLEGE    OF   DENTISTRY 
UNIVERSITY    OF   CALIFORNIA 


